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.
Then Michael Turner rescued a share of the spoils for Chris Hughton's side with a late equaliser.
Lambert said: "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.
"But, looking at it again, I think Elliott, too, has had hold of Joe. It was a bit of an even contest and I think the two of them were at it.
"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."
Lambert insists being up against the team he led to successive promotions had not crossed his mind.
He said: "It didn't enter my head at all, not a thing. This is my club.
"It's a brilliant club, I know the lads like back of my hand but it's Chris' team, Chris' club.
"I'll forever be thankful for what those Norwich players have done. But it never bothered me."
Lambert confirmed winger Charles N'Zogbia will be out of action for "some weeks" with a knee ligament injury suffered in training on Thursday.
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.
"You can look at the game apart from possession, balance of play and amount of ball in the final third, as one of three clearcut chances.
"They had one and Benteke put it away. We had two with Wes Hoolahan and Grant Holt and we didn't but I thought having gone down 1-0, we came out second half with a good attitude and forced the issue.
"I think I would have been confident enough we would have got back in the game even with 11 men."
Hoolahan was a constant threat in addition to setting up Turner's equaliser.
Hughton said: "He is a wonderful player. He is no different to what I thought before I came here.
"I always thought he was a superb player. With Wes, it's about getting him into the team, which way you are going to play, are you going to play two out and out strikers.
"Whether Wes is in the team or not, it will not change my opinion of what a good player he is."