Villa went ahead through Christian Benteke but Bennett was sent off early in the second period for a second bookable offence after a foul on Elliott Bennett and then Michael Turner rescued a share of the spoils for Chris Hughton's side with a late equaliser.
"I think the sending off changed a lot. That changed the game. At first thought I thought it was a sending off, because when you commit a foul and you go to do something, then you put yourself in a position where you can get the red," said Lambert, "But, looking at it again, I think Elliott, too, has had hold of Joe."
He added: "I haven't had the chance to talk to the ref (Phil Dowd) about it yet. I've only just watched a tape of it.
"But I thought the team were brilliant with the way they defended strongly after that."
Villa remain just above the relegation zone but Lambert is convinced his side will steer clear of trouble despite having to face Sunderland, the two Manchester clubs and Arsenal in their next four league games.
He said: "Will Villa will be okay? I have great belief we'll be totally fine.
"You know what you're going to come up against in the games coming up but those games will take care of themselves. You won't need to lift anyone for these games. I've got great belief in the players that won't change. I always go into every game believing we'll win it and I won't change my thinking."
Hughton was disappointed his side failed to follow up the win over Arsenal last weekend with three more points.
He said: "I think it was two points that got away. When you are 1-0 down, you are delighted to get back in the game. If it's 0-0 and you have the pressure we had at the end, you are more disappointed."