After losing to Aston Villa last weekend, Carlo Ancelotti's side responded in emphatic fashion by ruthlessly seeing off the challenge of Blackburn and making it nine goals in the last two games at Stamford Bridge.
Gael Givet turned the ball into his own net to open the scoring, before Lampard fired in his first goal from open play in the league this season at the beginning of the second half. Michael Essien added a third with a curling long range effort and a Lampard penalty and header from Didier Drogba completed the rout.
Aston Villa failed to make up ground on the leaders as they were held 1-1 by Wolverhampton Wanderers at Molineux.
It looked as though Martin O'Neill's side had taken all three points when Gabriel Agbonlahor pounced on 79 minutes, but just four minutes later the home side were awarded a penalty kick and Sylvan Ebanks-Blake made no mistake to score his first Premier League goal.
Sunderland were brought back down to earth at Birmingham, with the Blues running out 2-1 winners. Liam Ridgewell and James McFadden netted either side of half-time to put them in control of the match and although a late Scott Dann own goal gave the Black Cats hope it wasn't to be.
Stoke City picked up their first away win of the season to stun Tottenham Hotspur at White Hart Lane.
Stand-in goalkeeper Steve Simonsen put in an inspired performances after Thomas Sorensen was taken ill before kick-off. He made a series of saves to deny Spurs before Whelan struck, keeping Stoke in ninth in the table. It means Spurs missed the chance to go top of the table, for a short time at least.
Burnley's 100% home record in the Premier League came to an abrupt halt against Wigan Athletic. Steven Fletcher actually put the Clarets in front after only four minutes but it went badly wrong when goalkeeper Brian Jensen was injured as Hugo Rodallega levelled on 11 minutes.
The final game of the day saw struggling Hull City and Portsmouth play out a dour goalless draw.