The clean sheet at The Hawthorns also broke the record for a team going so long without conceding a goal. United have not conceded a goal in the League for 11 matches - that being against Arsenal way back at the beginning of November.
"The defensive record is a fantastic performance and it is down to the experience we have gathered together in the back four," Fergie said after the match.
"Even though we've had to make changes in the last few weeks because of injuries, they have all applied themselves very well.
"Edwin van der Sar, who has achieved everything in the game, is as delighted as when he saved that penalty kick in Moscow during the Champions League final.
"He was over the moon in the dressing room and that tells you his desire. He has still got that ambitious streak and wants to win all the time."
"We saw a ruthless streak that has maybe not been there this season.
"We hoped it was going to come. We expected it to come because of the standard of forwards we have.
"Tonight was the first indication that it was there. For the first ten minutes West Brom did very well and gave us a bit of defending to do and we were quite resolute at that stage of the game.
"But once we got the ball in their half of the field, we always looked dangerous."