Lionel Messi scored a hat trick as Barcelona thrashed Manchester City 4-0 at the Camp Nou on Wednesday.
Messi opened the scoring in the 17th minute with a cool finish past former Barcelona goalkeeper Claudio Bravo, who was sent off for handling outside his penalty area after half-time.
Ilkay Gundogan forced a fine close-range save from Marc-Andre ter Stegen on 38 minutes and John Stones' header flashed wide in the 45th, but City were two down when Messi cut inside to beat substitute keeper Willy Caballero at the near post.
Messi grabbed his hat trick eight minutes later but Barca were also down to 10 men when Jeremy Mathieu was sent off for a second yellow card and Neymar -- who had earlier missed a penalty -- completed the scoring.
In-form Arsenal produced a dominant display illuminated by a Mesut Ozil hat trick as they breezed past Ludogorets 6-0 at the Emirates.
The Gunners made the breakthrough in style after 12 minutes when Alexis Sanchez cut in from the left and beat goalkeeper Vladislav Stoyanov with a delicate chip, and Theo Walcott fired home a brilliant second after 42 minutes.
Less than a minute into the second half it was 3-0 to the North Londoners as Alex Oxlade-Chamberlain seized on a loose ball inside the Ludogorets area and slammed home an emphatic finish.
And as Ludogorets crumbled, Ozil took over to complete the easiest of victories.
Bayern Munich scored two early goals as they eased to a 4-1 victory over PSV Eindhoven at the Allianz Arena.
The Bundesliga champions were rewarded for an attacking start when Thomas Muller smashed home at the second attempt after an Arjen Robben corner fell to him on 13 minutes.
Within seven minutes Bayern had doubled their advantage, David Alaba's deflected cross falling perfectly for Joshua Kimmich to head home from close range, but the Dutch champions pulled a goal back in stunning style four minutes before the break as Luciano Narsingh raced on to a Gaston Pereiro pass and lashed in an effort from distance that Manuel Neuer was unable to keep out.
After the break, Bayern restored their two-goal cushion when Arjen Robben's shot was saved but the ball bounced to Robert Lewandowski, who headed home from close range, and Robben headed home the fourth at the end of a slick passing move.
Napoli were stunned as Besiktas snatched a 3-2 win at the Stadio Olimpico.
After early pressure from the home side, Besiktas went ahead when a poor clearance enabled Ricardo Quaresma to fire in a low cross for Adriano to score from close range.
But the Serie A team were level after half an hour as Dries Mertens finished a fine move involving Marek Hamsik and Jose Callejon -- but within moments a terrible backpass allowed Vincent Aboubakar to run on and fire in off Pepe Reina to restore the visitors' lead.
Napoli missed a golden chance to equalise from the spot when Insigne had a penalty saved soon after half-time -- but when Napoli were awarded another after 69 minutes, substitute Manolo Gabbiadini made no mistake.
Gabbiadini thought he had found a winner when he fired home an overhead kick from close range, but the offside flag denied him -- and Besiktas snatched it when Aboubakar headed home Quaresma's free-kick close to full-time.
Paris Saint-Germain bounced back from a sluggish start to win 3-0 against Basel at the Parc des Princes.
The French champions twice came within a whisker of conceding the opening goal as first Michael Lang and then Seydou Doumbia hit the woodwork, with Doumbia also blazing a good chance over the top from close range.
They made their visitors pay for not taking those chances when Angel Di Maria lashed home after Edinson Cavani had laid the ball off to him.
Lucas Moura put the French champions into a comfortable lead when he seized on a poor clearance inside the area to slide home a low finish for the second, and Edinson Cavani rounded off a comfortable night from the penalty spot.
Atletico Madrid saw their perseverance pay off in a 1-0 victory away to Russian side Rostov.
Atleti made an early statement of intent as early as the second minute, with Rostov goalkeeper Dzhanaev parried a free-kick from Yannick Carrasco out to Angel Correa, whose effort from an angle flashed beyond the keeper but also past the far post.
Carrasco soon forced Dzhanaev to make another stop, but Atletico were becoming frustrated by their inability to break through and Sardar Azmoun tried his luck with a couple of speculative efforts for the Russian side.
But Atletico got the reward their dominance had deserved after 62 minutes when Carrasco smashed home a half-volley after Juanfran's cross.
Celtic defender Kolo Toure suffered an evening to forget as Borussia Monchengladbach won 2-0 in Glasgow.
A high-octane start from the home side brought Gladbach goalkeeper Yann Sommer racing out of his area to clear a through ball as Moussa Dembele ran through. But Celtic counterpart Craig Gordon was soon into the action himself, stopping two Ibrahima Traore efforts and denying Jonas Hofmann.
Scott Sinclair could have given them the lead against the run of play when he fired over close to half-time, but Gladbah made a deserved breakthrough after half-time as Toure was caught out by Andre Hahn as he tried to usher the ball behind for a goal-kick and Lars Stindl lashed a low, angled shot through Craig Gordon at the near post.
And Toure's terrible pass enabled Hahn to race clear and prod a finish into the top corner under pressure from the defender.
Dynamo Kiev were left to rue a slow start as they lost 2-0 to Benfica at the NSK Olimpiyskyi
The visitors carried all the threat in the opening stages and were in front after only nine minutes when Eduardo Salvio scored from the spot after Vitorino Antunes had brought down Goncalo Guedes inside the area.
And the Portuguese side doubled their lead soon after the break when Franco Cervi slotted home at the second attempt after his first effort had ricocheted back to him off a teammate.