Arsenal will need to find a way to stop Premier League top scorer Jamie Vardy when they take on Leicester in a title-race showdown on Sunday. Laurent Koscielny will have a key role in that, and Vardy certainly won't be underestimated by the man he refers to as "the best I've played against".
"He's quite quick, and a big lad," Vardy told The Times. "I'm not too bad in the air but I wasn't winning any headers off him. When I was having a run at him, he was keeping up with me as well."
With the winner of this particular contest being so pivotal to the game's outcome, Karl Sturgeon takes a look at the details you need to know…
It's starting to look as if Leicester can do it. Last week's win at Manchester City was a masterclass in winning away from home - and the Foxes now go to the Emirates with the Premier League's best away record.
Leicester have taken 28 points away from home - over the previous five years, the champions took on average of 34.4 away points across the entire season. They have already beaten Manchester United's tally of 25 points in the 2010-11 title-winning season, and if they keep this form up they are projected to take 41 points by the season's end.
Leicester are built to counter-attack. They average just 40.92 per cent of the ball - only Sunderland and West Brom average lower. Arsenal, unsurprisingly, are one of six teams to average more than 56 per cent possession this season.
When Leicester win the ball they move it forward quickly - Claudio Ranieri's side lead the Premier League for passes into the final third with 1904. For some context, despite Arsenal's tendency to dominate possession the Gunners have made 1545 passes into the final third. Twelve teams have made more.
So it's a safe bet that the majority of Sunday's play will take place inside Leicester's half. Just how they like it…
Jamie Vardy is a key part of Leicester's counter-attacking style. Vardy's top speed in the Premier League this season is 35.44 km/h, considerably faster than the top speeds clocked by any of Arsenal's main three centre-backs.
Leicester use Vardy's pace well. For instance, all four of Danny Drinkwater's Premier League assists this term have been for Vardy goals - and three of those assists were passes from deep that Vardy ran onto. Arsenal's relative lack of pack leaves them vulnerable - only two teams have conceded more goals on the break this season.
Vardy's form and pace on the break mean Laurent Koscielny will be crucial on Sunday.
Last month, Arsene Wenger likened Koscielny to Italy's World Cup-winning captain Fabio Cannavaro. Wenger described the qualities Koscielny had demonstrated prior to joining Arsenal, at French side Lorient: "[He was] not too tall but very mobile, read the game very well and had great interception qualities."
Great interception qualities indeed - this season he's made comfortably more interceptions than any other defender in the Premier League, 12 more than the next-best player, his team-mate Nacho Monreal.
This is a peculiar facet of Arsenal's play - Wenger's side have made 482 interceptions overall, the fifth most in the Premier League. It's generally the sides who see less of the ball that rack up those kinds of numbers - in fact, of the top seven teams for interceptions, only Arsenal average more than 50 per cent possession.
Given the importance of interceptions to a counter-attacking style of play, it's not surprising that Leicester lead the way.
Arsenal beat Leicester 5-2 away earlier this season. Jamie Vardy scored twice but was outdone by a hat-trick from Alexis Sanchez. Leicester have improved defensively since then, conceding two goals in their last seven League games and keeping five clean sheets in the process.
As the scoreline suggests, the game at the King Power was settled by attacking quality rather than defensive resolve. The Gunners made 14 interceptions, with Koscielny contributing three of those - unusually low for both team and player alike.
Given Leicester's new-found solidity at the back, it's unlikely that Arsenal will score five again on Sunday - but Jamie Vardy is still as much a threat as he was back in September. If he scores twice again, that could be enough to take Leicester even closer to the unthinkable.
If Arsenal want to maintain their title challenge on Sunday, they'll need Koscielny's reading of the game to be at its best.