"That may have had something to do with why we played as poorly as we did," said the Baggies boss after the 1-0 win.
"The fact that we were stressing it so much before the game maybe put them under a bit too much pressure and we didn't play relaxed football.
"If ever there was a case of a side being disappointing in the way we played, but getting a result, that is it."We had a lot of players playing well below how they can play.
"It wasn't a good night as regards the way we played, but it is a really good result.
"It wasn't 'tally-ho' football, but we were a lot more open than we normally are.
"We didn't leave it late on purpose, I just don't remember us causing them too many problems apart from the last ten or 15 minutes."