Holt scored his sixth goal in eight matches and Lambert praised the burly striker.
"Holt has been great for the last two-and-a-half years I have been here," he said. "I think he has scored 50-odd goals in 100 or so games and in anyone's book that is a phenomenal ratio.
"He has always been a handful and it is a great testament to him he is probably getting the reward from it.
"It was a brilliant finish. I thought the free-kick, Steve Morison's lay-off and the way he rolled (John Heitinga) was excellent.
"He seems to be doing it again so I am delighted for him and the lads."