Chelsea manager Andre Villas-Boas wants nothing more than for Manchester United and Manchester City to suffer a drop in form before Christmas.
Chelsea's 2-1 victory over City on Monday, which ended Roberto Mancini's undefeated start to the Premier League season, breathed life back into the Londoners' title hopes.
"Nothing is going to be decided in December or January, but this is a stressful situation between the Manchester clubs," Villas-Boas said. "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.
"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 Manchester 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."