Premier League leaders Chelsea kept up their 100% start to the season with an efficient display against dogged Stoke.Frank Lampard had an early penalty saved by Thomas Sorensen before Florent Malouda fired in the opener after latching on to John Terry's fine pass.The visitors were unlucky not to equalise when Glenn Whelan thumped a 30-yard effort against the crossbar.But Didier Drogba wrapped up the win with the champions' second spot-kick after Sorensen tripped Nicolas Anelka.The Potters provided a far sterner test than West Brom and Wigan - Chelsea's previous two opponents in a free-scoring start to the season - but they were unable to stop Carlo Ancelotti's side chalking up an eighth straight home league win.While a third successive 6-0 victory never looked on the cards in a comparatively low-key Blues display, the result was rarely in doubt aside from a moment midway through the second half when Whelan's superb effort bounced down off the underside of Petr Cech's bar.Chelsea had scored an outlandish 29 goals without reply in their previous five home matches - including a 7-0 rout of the Potters in April - and they almost added number 30 within the first five minutes. Ashley Cole latched on to an exquisite through ball from midfielder Michael Essien but the England left-back dragged his shot wide of Sorensen's far post.At the other end, Matthew Etherington looked the visitors' most potent threat and his cross from the left wing was hooked narrowly over by Jon Walters.Stoke almost ruined their vaguely promising start when Ryan Shawcross made a rash challenge on Malouda in the box and referee Martin Atkinson awarded a penalty.Lampard stepped up to take the spot-kick but Sorensen got down to his left and held the England man's soft, side-footed effort - making it a third penalty miss in a row for the midfielder.But that was as good as it got for the visitors and Chelsea, undeterred by Lampard's miss, soon broke the deadlock with a trademark goal of devastating simplicity.Terry stepped out of defence and broke through the middle before threading a perfectly weighted pass to Malouda, who clipped first-time past the onrushing Sorensen from 17 yards.The Blues almost added a stunning second when the ball was lofted into the box and Cole turned and lashed a fearsome volley against the crossbar.Chelsea's three-pronged attack of Anelka, Drogba and Malouda were a constant menace and just after the break, Frenchman Anelka teed up Drogba with a dinked cross but the Ivorian's powerful close-range header was straight at Sorensen.Rory Delap's ever-reliable throw-ins presented Stoke with a good chance when the Irishman's long hoist was punched unconvincingly by Cech straight to Etherington, whose goal-bound shot was blocked by Drogba.The Potters then went agonisingly close to a leveller when Whelan walloped a long-range strike against Cech's crossbar with the home side's keeper beaten.But just as the visitors' hopes of an unlikely equaliser began to soar, the Blues notched a decisive second goal - after another easy penalty decision for referee Atkinson.Sorensen, who had previously put in an exemplary display, tripped Anelka on the edge of box and Drogba made no mistake from 12 yards with a thumping finish into the top left corner.Substitute Salomon Kalou should have made it 3-0 with a one-on-one late on but Sorensen stood up well to foil him.But it was another solid performance from Chelsea, who remain the only team in the Premier League with an unblemished win record, while the Potters are one of only two teams still without a single point.Credit: BBC