"It was a massive result for us, we won by battling and showing courage rather than some of the other qualities we normally use," Sir Alex told MUTV.
"In my experience of winning leagues in the past, we’ve always had to have this kind of game when everyone’s had to battle to get through it. We had to battle really hard today."
The need to roll up the proverbial sleeves was far from apparent in the opening stages of the game when the Reds took an early lead through Wayne Rooney.
"It was a great start," agreed Sir Alex. "In that first ten minutes or so I was thinking we’ve got a great chance here. But credit to West Brom, they kept playing their football and kept having shots from outside the box. They got their reward for that with their equalising goal, it was a tremendous hit. Then there were a couple of times when (Graham) Dorrans made the runs through the middle and caused us a bit of anxiety and I was just glad to get to half-time at 1-1."
One such anxious moment came when Dorrans' run was halted by a Gary Neville challenge inside the area. West Brom players and fans appealed strongly to referee Chris Foy for a spot-kick - to no avail and to the relief of the Reds' manager.
"I think it was a penalty," said Sir Alex. "At the time I didn’t, I thought Gary got a touch on the ball but having seen it again, I’d say Gary was lucky."