Goals from Chris Humphrey and Michael Higdon, either side of Giorgos Samaras' second-half equaliser for Celtic, gave Well victory to lift them up to second in the Scottish Premier League table and 19 points behind Wednesday's opponents.
On Saturday, McCall was heavily critical of his players after they were beaten 3-0 at Ross County but he was full of praise four days later following their impressive victory over Neil Lennon's side.
"We needed to bounce back after Saturday," McCall told Sky Sports. "We came out tonight and played a pressing game and the lads gave everything and I am delighted for them and the supporters.
"It is a big win for us looking at the league table and the top six. Overall, I'm very proud."
McCall also called for his players not to allow the standards they set themselves on Wednesday to drop when they face struggling Hearts this Saturday.
"It is no good putting in a performance like that and then going to Hearts and not playing like we can," added McCall.
"You can't not give desire and enthusiasm. They should be givens on a football field. We had that tonight but I also thought we had quality at times, defended well when we needed to and got a bit of luck when we needed."