The Baggies managed a 2-2 draw against United at Old Trafford, despite being two goals down before the break.
Olsson admitted: “We weren’t as solid as we have been and they had enough chances to put the game away.
“But when you play against some of the best players in the world you expect that kind of thing.
“The thing is, when you have been down a few times, you have it in the back of your head that if you fall behind again you can come back.
“We just felt if we got a goal, United would start to get a bit nervous. We took advantage of it.
“After that, we could have taken more, although a draw at Old Trafford is still a very good result.”
