Lambert told the club's official website: "I didn't think there was much in that. The scoreline was pretty harsh on us. We started the game great, looked really good, had plenty of the ball and looked very threatening, then Westy scores a terrific free-kick.
"We lost a poor goal with the header but Wayne Rooney can do that. The second goal was a penalty, a clear penalty. Then we came out in the second half and Christian has a really good chance.
"I won't be critical of him, though, because he's scored vital goals for us. But overall, we were definitely a handful. I always felt we could get something out of the game. But when you come to places like this, you have to take your chances when you get them."
Villa are 13th in the Premier League, nine points clear of the relegation zone.