Andre Villas-Boas believes Chelsea have ensured a "stressful" Christmas for Manchester City and Manchester United by storming back into the Barclays Premier League title race.
The past three weeks have seen Villas-Boas' Blues almost halve what was a 12-point gap to leaders City, while victory at Wigan will see them close to within just four points of top spot.
Villas-Boas said: "Nothing is going to be decided in December or January, but this is a stressful situation between the Manchester clubs. So that gives us, the people chasing, the chance to shorten the distance. In four games in the Premier League, we reduced the distance by five points."
He added: "We play Tottenham, we play Wigan, Aston Villa and Fulham. If we are able to shorten by another five points, it would be magnificent, but I wouldn't say that would happen.
"It's Man City-Arsenal being played this weekend and, again, this can have an influence on how the Premier League top four and five can look at the end of December."
Villas-Boas knows his side must keep winning to maintain the pressure on City, who he is not expecting to go into meltdown after Monday's controversial loss at Stamford Bridge.
"It's not the first time that they've suffered defeat," he said.
"It's the first time in the league, of course, but it's not the first time that they've suffered a defeat this season and they've responded magnificently well."
Victory against Wigan would maintain Chelsea's 100% record since the start of the month, a run that has coincided with Villas-Boas abandoning his much-maligned high defensive line.
But he said: "Our defensive organisation was never, ever in question. High line, or low line or whatever line, Liverpool are the best defence with 13 (conceded), then it's Man City with 15, and we are on 18. So I would say that we are pretty much a good defensive, solid organisation."