The new season is almost upon us and Europe's top clubs are busy setting their goals for the campaign. Here's what we can expect.
PREMIER LEAGUE
Best case scenario
Becoming the first club in a decade to retain a Premier League title, but also showing some know-how in Europe to go the distance. Last season's Champions League quarterfinal collapse against Liverpool was a significant asterisk against the achievements of Pep Guardiola and his squad, but this is a squad -- still improving, still being reinforced at great cost -- that should be semifinal regulars in the long term.
Worst case scenario
Their attacking game gets found out; they go through a crushing injury crisis; Claudio Bravo has to go back in goal; Guardiola blows his top after being asked one too many infuriating prematch questions; they're dumped out of the FA Cup by Wigan for the second season running and they still finish second in the league.
Make or break player
Kevin De Bruyne's furious perfectionism kept City on the front foot for about 95 percent of last season. He may not wear the captain's armband, nor roar the team out of the tunnel, but he sets the sky-high standard. The question is simply whether there are any positions left on a football pitch that he hasn't carved out a goal scoring chance from.
Best case scenario
Jurgen Klopp delivers what the Liverpool fans have been craving since 1990: a league title. The additions of an elite-level goalkeeper in Alisson, an all-purpose midfielder in Naby Keita, versatile defender Fabinho, and a shrewd Plan B in the unique shape of Xherdan Shaqiri have all plugged last season's most notable gaps. The Premier League trophy has changed hands nine times in nine years -- it could manage a tenth.
Worst case scenario
Mohamed Salah experiences his difficult second album; Alisson drops a high-profile early clanger or two and never quite recovers; that defence starts leaking again and Klopp -- smile a little more forced by this point -- finds himself in a bloody battle for the top four.
Make or break player
With Salah's temperament beyond question, he should deliver. In which case, it's Alisson -- at £65m the most expensive goalkeeper of all time by a huge margin, and the successor to a lengthy line of ultimately unreliable Anfield No. 1s -- who shoulders the big pressure going into the season.
Best case scenario
Jose Mourinho's performatively miserable brand of preseason expectation management turns out to be merely the preliminary mind games to a classic Mourinho season: punishing the weak, strangling the will to live out of their supposedly more attractive rivals, and turning siege mentality into a trophy or two.
Worst case scenario
Mourinho's performatively miserable brand of preseason expectation management turns out to be straw that breaks the camel's back before Christmas, and he storms off to another elite job somewhere else. Ed Woodward then has to find a stop-gap manager for a club that simply doesn't do stop-gap managers, the dressing room revolts, and United almost lose an official noodle partner next summer.
Make or break player
Paul Pogba returns to Old Trafford from his brief summer break as a World Cup winner. Whether it's down to how Mourinho's system can accommodate his expansive talents, or whether Pogba himself can find a way to become more influential on a weekly basis, it will surely once again be the central on-pitch issue for United's season.
Best case scenario
At the 13th time of asking, Chelsea finally stumble upon a manager who: a) can deliver the sort of entertaining football Roman Abramovich has craved since 2003. b) will ask politely for some new signings before ultimately making do with whatever he receives. c) win a trophy. Nothing too earth-shattering -- perhaps a Europa League/EFL Cup double, 100-plus goals and several thousand retweeted videos of their counter-attacks.
Worst case scenario
Abramovich realises - again -- that spectacular football can't just be transplanted from one club to another in the space of about three weeks. Chelsea struggle to keep all their plates spinning, go out of the Europa League to Sarri's old club Napoli in the quarterfinals, fail to secure a top four spot for the second season running, and Eden Hazard is sold to Real Madrid for a painful fraction of what they might have paid this summer.
Make or break player
For all the upheaval, Chelsea still boast a strong squad. The last piece of their post-Diego Costa jigsaw is still up front, where they will hope Olivier Giroud's match-turning presence motivates Alvaro Morata into producing a full season of intelligent runs, deft headers and nerveless finishing. It's far from guaranteed.
Best case scenario
Riding on a wave of new-stadium enthusiasm after an up-and-down tenancy at Wembley, Spurs finally consign the generation-old footballing adjective of "Spursy" to the dustbin of history and secure their first silverware in a decade by winning the FA Cup at Wembley. Meanwhile, Mauricio Pochettino resists Real Madrid's magnetic pull for another summer.
Worst case scenario
Daniel Levy's transfer-window intransigence is beaten by the clock, and Spurs go into the new Premier League season with (oh, the humanity!) exactly the same squad as last season. Despite Pochettino's work ethic, they stand still while Liverpool, Chelsea and Arsenal move firmly into the ascendancy. Momentum lost, promising work undone, "Spursy" remains in the football dictionary, the St Totteringham's Day countdown starts up again, and Pochettino takes a deep breath before heading into the Bernabeu boiler room.
Make or break player
Scoring 135 goals in four seasons, despite a seemingly relentless schedule for club and country, is a high bar to keep reaching. Harry Kane looked shattered once England's unexpected World Cup campaign finally came to a halt in the semifinals, and yet is still only a few days into his mid-20s. As long as he doesn't burn out, nor will this Tottenham side.
Best case scenario
Unai Emery, with a whole summer to redecorate Arsene Wenger's old office and with Emirates expectations at a sensible level, rids Arsenal of their decade worth of inertia with an instant impact. A top-four finish, secured without any early-May suspense, would be considered a very solid start.
Worst case scenario
A David Moyes-style malaise resulting from a second-hand squad that needs careful rebuilding and made even more laborious by a notoriously demanding fanbase whose goodwill evaporates in an instant.
Make or break player
It's tempting to reach for the broken record labelled "Mesut Ozil's Inconsistency" but, in the spirit of new starts, the newly-acquired Lucas Torreira may be the most interesting one to watch. Arsenal's soft middle just got a lot more solid. Even the neutrals are hoping for something different from the Premier League's ever-repeating Groundhog club, and the 22-year-old bundle of Uruguayan energy might be the catalyst they need.
EUROPE
Best case scenario
A fourth La Liga title in five seasons, secured in as emphatic a fashion as 2017-18, where they led all the way from early September to ease over the line a full 14 points clear of Atletico Madrid. After that, things get trickier: their devastating/hilarious (delete as appropriate) Champions League collapse against Roma will take some serious avenging, and that has to be Ernesto Valverde's second-season priority.
Worst case scenario
It is five years since Barcelona went without a major trophy; eleven years since they failed to win a trophy at all. They have won the league and cup double three times in four years. That's the absurd benchmark they're working to these days so, once again, it's to Europe we'll look to judge Ernesto Valverde's follow-up season. Anything less than a quarterfinal berth and their domestic dominance won't be enough to call off the critics.
Make or break player
Lionel Messi, and not just because he's Lionel Messi. At 31 years old, and with his perennial rival Cristiano Ronaldo having finally moved on to another league, there is a sense that there is a final chapter approaching. Another soul-sapping World Cup with Argentina will, however, make the week-to-week slog of La Liga feel like home.
Best case scenario
An appropriately stellar replacement for Ronaldo, a far more robust challenge to Barcelona for the title, and yet another lengthy Champions League run. Very much in that order. Meanwhile, after his highly unorthodox start in the job, Julen Lopetegui will need to convince everyone at the Bernabeu -- and not just in the expensive seats -- that he can pick up where Zinedine Zidane left off.
Worst case scenario
The €100m from the Ronaldo sale burns a hole in their pocket while the likes of Eden Hazard and Neymar stay put; Gareth Bale -- finally with the chance to step fully out of Ronaldo's shadow -- finds his body letting him down again; Lopetegui struggles to juggle the Bernabeu egos. Meanwhile, Barcelona and Atletico go about their business above them.
Make or break player
With or without a new headline arrival this summer, Real Madrid need Gareth Bale to play more than 30 league games and assume that the goals will follow. He has the stature and the temperament to handle the task, but don't expect the same level of on-pitch theatrics as the previous main man.
Best case scenario
Continuing to be a uniquely irritating thorn in the sides of Spain's "Big Two" on the domestic front, while hoping that Diego Simeone's "thou-shalt-not-pass" gameplan negotiates a few knockout rounds of the Champions League.
Worst case scenario
The relentless demands of "Simeoneball" finally taking its toll on the older legs in the squad, with Diego Costa deciding it's time for another series of his soap opera, and the club finishing a very distant third in La Liga.
Make or break player
Antoine Griezmann made the stage-managed, mid-World Cup decision to stay with Atletico, where he has been their top-scorer for four years in a row. He is now into Fernando Torres territory of mutual adoration with the fans, and that's a precarious place to be.
Best case scenario
An eighth Serie A title in a row, obviously. But now, with "The Cristiano Ronaldo Experience" setting up in Turin, it is a chance to turn themselves from Champions League bridesmaids to winners for the first time since 1996.
Worst case scenario
An eighth Serie A title in a row. The chasing pack aren't much closer. But Champions League progress is the key.
Make or break player
Whatever we know about Ronaldo, however many times he delivers at the crucial moments, you still can't help but feel that €100m for a player who'll be 34 by the time the Champions League knockout stage begins is something of a gamble. Now watch him prove you wrong.
Best case scenario
New manager Niko Kovac to deliver a seventh straight Bundesliga title for Bayern, again wrapped up with half a dozen games left to play, after doing what Bayern always do -- hoovering up the brightest Bundesliga talent for themselves. Leon Goretzka should slot in perfectly.
Worst case scenario
Hitting a Spanish brick wall, yet again, in the Champions League. Real Madrid (three times), Atletico Madrid and Barcelona have all halted Bayern's progress in Europe since they last lifted the trophy in 2013. Kovac will have to think of another way around it.
Make or break player
He's scored 151 goals in four seasons, but is neither young or glamorous enough to really tempt Europe's other big guns to test his club's resolve to keep him: Robert Lewandowski and Bayern Munich are stuck with each other, so it's time they got a Champions League trophy out of it.
Best case scenario
Another rampant Ligue 1 title, Neymar leaving his World Cup histrionics behind him to do what he was signed so expensively to do: drag PSG to the business end of the Champions League, with Kylian Mbappe and Edinson Cavani as his elite support acts, and let Gianluigi Buffon finally, finally lift that trophy.
Worst case scenario
Complacency and European distractions making their title defence more of an inconvenience than it should be, before they fall apart again in the Champions League quarterfinals at the hands of someone simply more streetwise, turning a habit into a hoodoo.
Make or break player
Forget Neymar for a second. Kylian Mbappe chose the World Cup as the moment to announce, at just 19 years of age, that he should be the next superstar of world football. And he did it without even a hint of arrogance. Few teenagers have ever looked so polished at top speed than this kid.