With Daniel Sturridge and Mario Balotelli ahead of him in the Anfield pecking order, Lambert has been forced to wait patiently for chances to impress since joining his boyhood club from Southampton in June.
But injury problems for Sturridge and Balotelli has seen Lambert handed a prominent role in recent weeks and he has taken full advantage of the chance, netting in back-to-back games against Crystal Palace and Ludogorets.
Lambert's all-round contribution has also impressed midfielder Lallana, who knows all about the 32-year-old's ability from their time at Southampton.
"He has been brilliant for us in the last four games, coming into the team," Lallana told the club's official website.
"He has contributed in every game with a goal or assist.
"He has worked hard for this moment and his run of games.
"I always knew he was going to turn the corner, and I'm delighted for him and the team."
Lallana was on target as Liverpool battled from behind to win 3-1 at Leicester City on Tuesday, a result that followed a 1-0 home success over Stoke City.
Reflecting on the Leicester game, Lallana added: "It was a huge result for us and that's back-to-back wins.
"It builds up to the game at the weekend nicely.
"It's a massive result for us. It has been a big week and we want to finish it well; we have got a great chance to get three points against Sunderland [on Saturday]. That's what we'll be aiming to do."