Jamie Murphy puts the visitors ahead in the 80th minute but the Dons snatched a 1-1 draw and a replay thanks to Niall McGinn's injury-time effort.
McCall said: "It's the second time we've been up here and lost a goal in the last minute, but if you'd said to me after three or four minutes that we'd get a draw, I'd have taken it right then.
"The first five or 10 minutes were an onslaught, and how we survived it I don't know. There was a bit of good goalkeeping, some good fortune, and some good defending.
"As much as Aberdeen have injuries, they still put out a very strong and experienced side, and we had two of our own young lads at centre-back - Fraser
Kerr and Adam Cummins got stronger as the game went on.
"We grew into the game, and I thought second half we were more prominent. It was a terrific goal from Jamie, and the lads are a bit gutted in the dressing room, but we're still in the hat and overall I think it was a fair result."