Lampard's side bounced back from their midweek League Cup defeat against Manchester United to make it five successive league wins.
The Blues have won eight of their past nine matches in all competitions as Lampard continues to make a good impression in his first season in charge.
His decision to go with unproven youngsters like Tammy Abraham, who opened the scoring, has been a shrewd move, while Christian Pulisic, scorer of the second, is justifying his hefty price tag after starting the season on the bench.
Gerard Deulofeu's late VAR-awarded penalty came too late to stop Chelsea recording a seventh successive away win in all competitions.
They are just two points behind second-placed Manchester City despite being unable to sign players in the summer due to a transfer ban.