Tony Pulis praised the effort of his players after yesterday's 1-0 victory over high flying Southampton.
It took the Baggies only 70 seconds to score the opening goal when Saido Berahino smashed home Craig Dawson's knock down.
Albion dominated the opening 25 minutes - despite working on a different formation all week.
"They changed their team. We didn't realise that until an hour before the game - so we changed ours a little bit too so we effectively had a diamond," Pulis said.
"I was really disappointed they changed their shape back because before that I thought we played well and had some good chances. In the second half we had to dig in. And we did that very well.
"But to get a result today is first class."