Chelsea turned on the style after the break as Lampard scored twice, Florent Malouda continued his goal-scoring form with a brace and Salomon Kalou came off the bench to also score in the rout.
Manchester United can reclaim top spot if they beat Bolton Wanderers in Saturday's late kick-off at the Reebok Stadium - live on ESPN
Kevin Phillips came off the bench to score a last-gasp equaliser for Birmingham City and earned a 1-1 draw at St Andrews to dent Arsenal's title charge.
Samir Nasri had given the Gunners the lead in the 81st minute and Arsene Wenger's side look set to keep the pressure on the Premier League leaders but Phillips' leveller leaves Arsenal in third place.
source: espn soccernet