Arsenal manager Arsene Wenger has called on the club's fans to show Cesc Fabregas "the respect he deserves" when the former Gunners captain returns to the Emirates Stadium in a Chelsea shirt on Sunday.

Fabregas, 27, has been integral to the Blues’ Barclays Premier League title challenge this season after joining from Barcelona in the summer.

Arsenal had reluctantly sold the Spain midfielder back to his boyhood club for €42 million in June 2011 and were understood to have first option should the player come back onto the market.

A potential deal never materialised though as Fabregas — who played more than 300 games for Arsenal after breaking into the first team as a 16-year-old — joined up with Jose Mourinho at Stamford Bridge instead.

It remains to be seen what sort of reaction the former crowd favourite will receive from home supporters on Sunday, but Wenger feels it should not be hostile.

“I want every player to be respected, and Cesc Fabregas when he comes to the Emirates on Sunday to be respected like he deserves,” the Arsenal manager said.

“The regret I have is that he wanted to leave here. This club and myself had a very positive influence on Cesc’s life, so I would be a bit uncomfortable to have to justify today why he is not here.

“I believe I would rather it was the other way around.”

Arsenal defender Per Mertesacker is rated as "50/50" by Wenger after the German hobbled out of last weekend's FA Cup semi-final win over Reading at Wembley because of an ankle problem.

Midfielders Mikel Arteta and Alex Oxlade-Chamberlain are both not yet in first-team contention following injury lay-offs.

Chelsea stand 10 points clear of Arsenal following their 1-0 win over third-placed Manchester United.

Wenger accepts that even if his side win on Sunday, it would remain a tall order to overhaul the leaders’ advantage in the five matches that follow before the end of the season.

“Mathematically it will be possible, but Chelsea have their future and the championship in their hands,” said Wenger.

“What we can do is get closer to them and we have an opportunity to do that at home. We want to take it.”

To reduce the deficit, Wenger must get the better of Mourinho for the first time.

Arsenal were thumped 6-0 at Stamford Bridge in Wenger’s 1,000th match in charge of the team last season, and the pair had to be separated when they went toe to toe in the touchline as Chelsea ran out 2-0 winners in the Premier League in October.

Wenger, though, played down suggestions it was all about the men in the dugout.

“I don’t want to talk about that because what is important is when the game starts at four o’clock, to have a great game,” he said. “That’s what English football needs, to know that Arsenal against Chelsea is a big game and is not about the relationship between the managers.

“It is not a confrontation (between managers), it is a confrontation of two teams.

“I am not a great believer in history. I just think football is down to the fact that the performance on the day will decide the game and the result, so let’s focus on that.”

Wenger added: “We have not always lost, first of all, in 12 attempts. We have come close to beating them a few times and they have always had very strong teams.

“We are on a good run and we have an opportunity to beat them at home, and we want to take it.”