Lambert was brought on as a second-half substitute to partner the Italian up front at Anfield, and the England international thought that his teammate did well prior to his own introduction.
He told the club's official website: "I thought he held the ball up, made runs and was just unlucky with a couple of chances. I want to be on there with him, I want to be playing of course. But I thought he did well.
"Mario, myself and every striker knows it's about what's best for the team, whatever way the manager wants to play, whether it's one or two up front. We have to give our best.
"Mario did superbly in the first half and in the second half he held the ball up - it's hard being the lone striker. When we were both on we managed to cause them more problems and had a few more chances."
Brendan Rodgers's side host his former club Swansea City in the League Cup on Tuesday.