"He did well," Lam said of Weepu. "It was his first time within the team. He called the shots and like a lot of the guys from last week and this week, was still rusty, just getting the cobwebs out."
Lam is still playing his cards close to his chest but it seems likely that Weepu, who shone at halfback in the World Cup, will remain at first-five for Friday afternoon's final pre-season hit-out against the Highlanders in Auckland, and stay there for the first game proper against the Crusaders.
The combination of the two former Hurricanes - Alby Mathewson at halfback and Weepu at first-five - is an exciting one and better than most in the competition.
Another World Cup winner likely to have to make a change is Jerome Kaino, named the All Blacks' best player of 2011 at blindside flanker.
Kaino played 40 minutes at No 8 against the Rebels, after also playing there against the Hurricanes in Whangarei, and Lam confirmed that would likely continue.
"During his first days with the Blues he played at No 8 as well but last year with the World Cup I was committed to him securing that spot and playing six. That was the focus last year, to ensure he not only played well for us but to give him the best chance at the World Cup. He's keen on both positions, obviously he's the best six in the country, but for us it's about where he is best suited for the players that we have."
Lam also has Brad Mika - who played the second 40 minutes - as a No 8 option, as well as Chris Lowery.
While Weepu was a little rusty, his opposite Cipriani - a former England international - was inspired and responsible for his side's first two tries, which he set up with his first two touches.
The Blues will name a squad of 22 for Friday's match at Unitec, after carrying squads of 27 for their first two pre-season matches.
Hooker Keven Mealamu and loose forward Luke Braid are likely to be available after recovering from surgery. Lam said wing Sherwin Stowers, who scored the Blues' first try against the Rebels, should be okay after hurting an ankle.
Rudi Wulf scored two tries after replacing Toeava at fullback, with hooker Tom McCartney also getting on the scoresheet.
Blues 31 (Sherwin Stowers, Tom McCartney, Rudi Wulf 2 tries; Michael Hobbs con, Munro pen, 3 con) Melbourne Rebels 21 (Cooper Vuna, Mark Gerrard tries; James O'Connor 3 pen, con)
HT: 18-7.