McGeady set up Marc-Antoine Fortune for the clinching goal which took the Hoops to within eight points of Rangers at the top table - but his overall display was recognised by the Celtic boss.
"I think Aiden benefited from the rest he had the other day," Mowbray said.
"You can't keep going back to the well with Aiden.
"He has been magnificent for five months for this football club but in the last month his performance level has dipped a little bit.
"However, against Hearts, especially in the second half, he was back to the exhilarating talent that he is, getting supporters out of their seats."
The much-changed Hoops are likely to be without six players who began the season in impressive form at Pittodrie, beating Aberdeen 3-1 on the opening day.
Massimo Donati, Danny Fox and Scott McDonald have left the club while Darren O'Dea, Andreas Hinkel and Shaun Maloney are injured.
Mowbray, with tongue in cheek, said: "We got praise for the performance? I can't remember that.
"Someone will tell me exactly how much the team has changed from the opening day to the team we play against Aberdeen but it has changed a lot.
"That day Maloney was out of this world, they changed their right full-back after 20 minutes because Maloney gave him a hard time.
"But Aberdeen will be prepared for us, we are expecting a tough game but I'm sure they are also.
"We will study Aberdeen and it might be a different team which played against Hearts but we will pick a team to get a positive result."
Mowbray played down the psychological advantage of playing 24 hours ahead of Rangers, who welcome Hibernian on Sunday.
Asked if playing first could be helpful in putting pressure on their Ibrox rivals, Mowbray retorted: "Not if we don't win the game.
"We have to go and get the three points and (if we do that) Rangers have to deal with the gap that will have been closed.
"If we don't win the game, I'm sure it will give Rangers a huge lift to win their match.
"It's all about us winning games from now on in."