Didier Drogba was Arsenal's tormentor again as Chelsea tightened their grip at the top of the Premier League. Arsenal paid the price for the failure to take the chances they created in periods of domination at Stamford Bridge - and for their continuing inability to contain Drogba as Carlo Ancelotti's champions stretched out a four-point lead over their title rivals. Arsene Wenger's side came close through Marouane Chamakh and Laurent Koscielny, while Andrey Arshavin brought a superb save from Petr Cech before Drogba struck his 13th goal against The Gunners as the interval approach. He applied a clever finish to Ashley Cole's cross to give Chelsea a lead that was against the run of play, but gave them a precious lead which they protected in trademark fashion. And for all Arsenal's pretty passing and intricate patterns in the second half, it was Chelsea who applied the killer blow five minutes from time when Alex concluded a fast bowler's run-up with a true touch of Brazil as he lashed a long-range free-kick high beyond Lukasz Fabianski. Wenger may take heart from the fact that Arsenal were not swept aside in the manner they were against Chelsea last season, although there were moments of slackness at the back, but there was no consolation in a familiar scoreline as they were once again beaten by their fierce London rivals. For Chelsea boss Ancelotti, attending the game despite the recent death of his father, there was satisfaction in the manner in which his side responded to their first Premier League defeat of the season at Manchester City. Arsenal, on the receiving end of comprehensive defeats against Chelsea at home and away in the Premier League last season, showed no inferiority complex as they almost scored twice inside the first 60 seconds. Chamakh's header from Bacary Sagna's cross was only inches away with Cech beaten, before Koscielny somehow headed the resulting corner over the top, despite standing almost on the goalline. And as Arsenal continued to dominate the opening exchanges, Arshavin forced a fine save from Cech and Samir Nasri was narrowly off target with a low drive. The threat of Drogba hung over Arsenal like a cloud, however, and he posted the warning signs by forcing a desperate block from Fabianski with an angled drive. Almost inevitably, for all Arsenal's superiority, it was Drogba who made the first half's decisive contribution as Chelsea went ahead after 39 minutes. Ramires did well to win possession before feeding Cole, whose near post cross was met with a subtle flick from Drogba that flew in via the near post. It was very much against the run of play - and Wenger's frustration was plain to see on the touchline. Arsenal refused to be discouraged by the setback and pressed forward with urgency at the back, but another moment of defensive frailty almost saw Chelsea double their advantage on the hour. Anelka robbed the hesitant Sebastien Squillaci, and even though he rounded Fabianski the angle was too acute and the finish rolled agonisingly wide for Chelsea. Arsenal were being punished for their wastefulness in front of goal, and Chamakh was the culprit again with 10 minutes left as he headed substitute Tomas Rosicky's cross wide. Chelsea's greater cutting edge was crucial, and they clinched the victory in spectacular fashion with five minutes left. Alex ripped a 25-yard free-kick high past the despairing grasp of Fabianski after Koscielny had been booked for a foul on Anelka. Arsenal were instantly deflated, and Fabianski had to make fine saves from Michael Essien and Cole as Chelsea threatened to extend the victory margin. Source: BBC