Chelsea 2 Middlesbrough 0: In this serene victory, it was easy to hear the numbers clicking into place in Chelsea minds.

Twenty-one fixtures have been completed and the side, thanks to Arsenal's draw, is seven points ahead in the Premiership as the club strive to be champions for the first time in 50 years. The other relevant figure was the pair of early goals by Didier Drogba for a squad that is hard to halt.

No one expects clubs to gorge themselves at the festive period, but Chelsea, Arsenal and Manchester United had all had their fill of points while winning each of their three matches. Should anyone retain a healthy appetite it ought to be the league-leading Stamford Bridge side and, with two goals before the interval, Drogba feasted on opportunities last night.

This sort of match, with all due apologies to the visitors, is the raw material of title challenges and Chelsea hardly ever fail to capitalise.

If their position at the head of the table was not exciting enough, a look at the Premiership fixture list for the three months until they go to Old Trafford must have been irresistibly thrilling.

With the trips to Arsenal and Liverpool already made, there were bound to be some ostensibly smoother paths before them. The team also appeared to find the going easy within this game. It was a good time to be meeting Middlesbrough, who were comprehensively beaten by Manchester United on New Year's Day and sorely miss the injured George Boateng to guard the defence.

Steve McClaren has a far more enterprising team nowadays, thanks to developments like the signing of Jimmy Floyd-Hasselbaink and the advent of Stewart Downing, but Jose Mourinho had considered them with his usual care.

Glen Johnson dropped to the substitutes bench, perhaps because someone who had been an erratic right back at Anfield was not to be risked against the rising talent of Downing. Paulo Ferreira was moved back to his normal berth, while the midfielder Alexei Smertin was the other full back, taking up a position he occasionally occupies for Russia.

Middlesbrough, brisk from the kick-off, showed that there was serious business to be conducted by the Chelsea back four, but a lack of durability was soon exposed. Following his second-half outing at Anfield, Drogba had more dynamism and self-belief than at any stage since his groin operation in the autumn.

The Ivory Coast striker fell upon the Middlesbrough defence like an avalanche after quarter of an hour. Arjen Robben laid the ball back to Frank Lampard and Drogba bounded onto Lampard's pass, to turn inside Gareth Southgate and shoot past Mark Schwarzer. He was just as unstoppable two minutes later.

Lampard hit a free-kick of intimidating pace from the left and the forward, getting in front of the overwhelmed Southgate, climbed to head home into the middle of the goals while Schwarzer was still trying to recover position after initially inching towards his far post.

Prior to the interval, there was much work to take the goalkeeper's mind off any regrets. Chelsea were playing with a gusto they have not shown for a few weeks but that was partly because the visitors had no means of checking their advances from deep positions.

Robben was especially sharp and he, as well as Damien Duff, might have extended the lead on a number of occasions in the first half, while Ferreira lobbed over the crossbar when Lampard sent him clear on goal.

As the evening proceeded, there were indications that Chelsea were managing their use of energy. A preference for counter-attacks developed and Smertin, who had been suffering with flu at the weekend, was allowed to resume his recuperation as Johnson took over in the 50th minute.

Convinced that their mission had been completed, Chelsea gave up a 2-0 advantage to draw with Bolton on this ground earlier in the season. It would have been helpful to Middlesbrough if Mourinho's players had been presumptuous enough to assume that their threat, too, was extinct.

The visitors might have taken heart at the progress they could now make into Chelsea's half, but they still ran a risk by doing so. From a move sparked by Cole, Duff thrashed a drive against the crossbar in the 57th minute.

With Arsenal fighting back to equalise elsewhere, Stamford Bridge became rather quiet. Such a modest level of decibels must be one of the sounds of success. It is the proper aural backdrop for tasks being completed conscientiously. Ear-splitting cries of horror still seem unlikely as Chelsea seek the championship.

CHELSEA: Cech, Paulo Ferreira, Terry, Gallas, Smertin (Johnson 50), Makelele, Lampard, Cole (Tiago 62), Duff, Robben, Drogba (Kezman 79). Subs Not Used: Gudjohnsen, Cudicini. Booked: Cole, Robben. Goals: Drogba 15, 17.

MIDDLESBROUGH: Schwarzer, Reiziger, Southgate, Cooper, Queudrue, Parlour, Doriva (Morrison 72), Zenden, Downing, Hasselbaink, Nemeth (Job 60). Subs Not Used: Nash, Davies, McMahon. Booked: Parlour.

Referee: S Bennett (Kent).