Lisandro Martinez has already cracked the code of keeping Erling Haaland quiet over 90 minutes. When the Manchester United defender played for Ajax in last October's 4-0 Champions League win against Haaland's Borussia Dortmund, the Argentina international worked in tandem with defensive partner Jurrien Timber to nullify the threat of the man now tearing the Premier League apart with Manchester City.
Haaland had chances to score in the Johan Cruyff Arena, but the defensive work of Martinez and Timber -- along with coach Erik ten Hag's tactical plan -- ensured that the game ended with Haaland suffering what, for him, has become the rarity of failing to score.
Almost 12 months on, Martinez and Haaland will face off against each other again on Sunday when Ten Hag's United travel to the Etihad in the first Manchester derby of the season. Both are in the early stages of their careers at their new clubs following summer transfers, and both have been two of the outstanding new arrivals into the Premier League this season. While there will be a number of key battles that will influence the outcome of Sunday's game, the Martinez vs. Haaland head-to-head will arguably be the most decisive.
If Martinez, likely with the help of defensive partner Raphael Varane, can enjoy another 90 minutes without allowing Haaland to score, then United's prospects of beating Pep Guardiola's team will be far greater. Yet Haaland is proving to be almost unstoppable in a City shirt.
In 10 games in all competitions for his new club, the 22-year-old has scored 14 goals and only Bournemouth -- yes, Bournemouth, who lost 9-0 at Liverpool -- have stopped him scoring in a competitive fixture. And even though he failed to net in City's 4-0 win against the Cherries, he still registered an assist, finding a way to make a telling contribution.
On paper, Haaland vs. Martinez should be a mismatch. The City forward stands at 6-foot-4 and has the physique of a heavyweight boxer, while Martinez is just 5-foot-9 and relatively slight, but what he lacks in physical advantages, the 24-year-old certainly makes up for in tenacity and his ability to read the game. After playing alongside Harry Maguire in United's opening two defeats against Brighton & Hove Albion and Brentford in the Premier League, Martinez's height -- or lack of -- was singled out by a number of respected former players as being an issue that would prevent him from becoming a success in English football.
"I'm convinced this can't work because the size of him [Martinez] playing in a back four," former Liverpool and England defender Jamie Carragher said after United lost 2-1 to Brighton and 4-0 at Brentford. "Maybe he could go left-back, maybe he could play in a back three, but in a back four, he cannot play there in the Premier League.
"His passing is very good, he looks aggressive. He looks like a leader. He's not a bad player, but to play at that level of football at 5-foot-9, I wouldn't want to play alongside someone who was 5-foot-9 as a centre-back."
Being small is not necessarily a critical disadvantage against a forward like Haaland. After all, the Norway international does not discriminate against certain types of defenders -- he scores against them all, whether they are big, small, fast or slow.
Former United defender Jaap Stam, a member of Sir Alex Ferguson's Treble-winning team in 1999, believes that Martinez has shown that he has the qualities to dispel the stereotype that small defenders cannot succeed in the Premier League. "That was an easy one, the day when he signed for United, I had already said they will talk about his height," Stam told the Manchester Evening News. "Over here [in England], everyone thinks as a centre-back you need to be big and tall, otherwise you won't make it.
"Of course, sometimes he's going to get surprised, but that's what also happens with big players -- they make mistakes as well. Martinez shows his quality on the ball, he shows his quality when defending and his communication around him is good. He just needs to keep going."
Against Dortmund, Martinez and Timber shared the defensive duties while marking Haaland. At 5-foot-10, Timber was also lacking in height and power against the forward, but with one defender dropping off while the other went close to Haaland, Ajax were able to prevent him from scoring.
At 6-foot-3, France international Varane will give United and Ten Hag a blend of height, strength and pace against City, which should make for a fascinating confrontation between City's goal machine and United's developing central defensive partnership.
But while Sunday will clearly be a test of the Martinez-Varane axis, it will also be a challenge for Haaland, who has yet to face one of the Premier League's so-called Big Six in a competitive fixture this season. In the Community Shield defeat against Liverpool in August -- a game that isn't classed as a competitive fixture -- Haaland cut a frustrated figure against Virgil van Dijk and failed to score in a 3-1 defeat. Haaland's most significant contribution in that game was missing an open goal from 3 yards out in stoppage time.
How Haaland fares against United will be an interesting pointer for the months ahead. If City's supply line to their star striker is reduced when facing top teams, Guardiola's side might not be quite as formidable as they have appeared against many of the Premier League's weaker teams.
Haaland is unquestionably a goal-scoring phenomenon and stopping him will be United's primary objective this weekend. In Martinez, though, they at least have a defender who knows how to do just that.