Abraham and Ross Barkley struck for the 2-1 win.
Lampard said, "I'm very happy this evening. Tammy is a goalscorer, hungry for goals, constantly wanting to score. I saw that in the Championship last season, he's proven that and now it's his time to prove it at Chelsea. Confidence is big for goalscorers so to get his goal will put him in good stead.
"Olivier Giroud came on and did very well as well. He shoed his different style and attributes he brings, and the same for Batshuayi. There's competition. People keep talking a lot about it and they all need to rise to the competition and show they can be strikers for Chelsea. I've got full confidence in them and it's great for Tammy."