The home side trailed 19-3 at the break before tries from Harry Randall, Piers O’Conor and Charles Piutau saw them claw their way back into the contest.
But Will Rowlands’ try sealed the bonus-point win for Wasps, leaving Lam to reflect on a “disappointing” evening.
“It was extremely frustrating and disappointing. We let everyone down, we know that, and the first 40 minutes was horrific,” said the head coach after the match.
“We have basically gifted them four tries, they didn’t have to work too hard for their points and we did. We came in at half-time and said look we need quicker ball, we need to tidy up.
“We built our way back into the game and then we gifted them another soft try, so all in all it was an extremely frustrating performance.”
“Let’s just can that and start again. We built our way back into the game and then we gifted them another soft try, so all in all it was an extremely frustrating performance,” he added.
“We just have to take it on the chin, regroup and move on. I though tonight some guys were world class, outstanding, but there were a few that weren’t and we all pay the price for that.
“That’s what we’re all about and it’s a team game. If we do the work and we do the job and nail our roles we all get the plaudits and if we don’t then we suffer the consequences.”