The striker scored his side's third goal in the 3-0 win over Fulham.
The striker joined on loan from Sunderland in the January transfer window, having found himself far down the pecking order at the Stadium of Light under Sam Allardyce.
He has made a decent start as well, bagging the third goal in his side’s 3-0 win over the Cottagers on Tuesday evening.
And Lambert says he is delighted for Graham, saying he will be a very good signing for the side if they can keep him fit between now and the end of the season.
"Danny Graham has scored at every level and it's funny because even when I was with Norwich, he was scoring goals with Swansea in the Championship,” he told Sky Sports.
"I always liked the way he played the game and there's always a hunger with him. You see his work-rate tonight, everything he gave us.”
"If there's one guy I'm absolutely delighted for to score a goal, it's him because he's a top guy, top pro and honestly if we can keep him fit, he will be a very good signing for us."
Blackburn could certainly do with someone coming in and scoring regularly considering they lost Jordon Rhodes in the January transfer window.
He had been their top goalscorer this season with 10 goals in 25 games, before his eventual move to Middlesbrough robbed Lambert’s side of their main goalscoring threat.
If Graham could come in and add some goals to help get over that loss, it will be a massive positive as they try to pull further away from the relegation zone in the rest of the campaign.