Two goals from Didier Drogba - taking his tally to 12 in 12 against Arsene Wenger's side - left the Emirates Stadium outfit nine points off the pace having also lost to Manchester United seven days before.
And Chelsea's No.1 believes it is now too big a gap for the Gunners to bridge.
"I think we have cut off Arsenal by this win and they will find it only very difficult to erase the nine-point gap at this stage of season, especially with the tough games they are going to play yet," he told his official website.
The result leaves the Blues two points clear of Manchester United at the Premier League summit.
The Czech stop-stopper said it was vital to beat the Gunners, and revealed the shut-out at Stamford Bridge on Sunday also marked a significant milestone for him personally.
"It could not have been better for me and the team," he said.
"We claimed a vital three points and it was my 100th clean sheet in the Premier League.”
Cech believes his side’s win over Arsenal was even more critical given Manchester United’s victory over Portsmouth 24 hours earlier.
And he stated that if Chelsea are to win the league, consistency over the final stretch is going to be key.
"For the rest of the season the important thing will be the consistency of results. The team which will drop the least amount of points along the way will win the league."
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