The Motherwell ace had come in for criticism after the 2-0 loss to Czech Republic in the Euro 2020 opener.
Manager Steve Clarke leapt to his defence in the build-up to the match at Wembley and he put in a stirring display which saw him nearly score with a volley.
O’Donnell picked up a yellow card for a late challenge on Jack Grealish
“I think I was just starting to get a wee bit fed up,” he told Scotland HQ.
“He had just come on and normally when the fresh wingers come on and you’re a wee bit tired you’re just thinking, ‘I need to hit him here’.
“I was getting fed up with him trying to take the mickey out of me so I gave him a wee hit!”
O’Donnell revealed he took some advice from team-mate John McGinn as to how to get in the midfielder’s head.
Grealish is a team-mate of McGinn's at Aston Villa and it provided some amusing anecdotes from his meeting with O’Donnell during the clash at Wembley which gave Scotland's chances of qualification a huge boost.
“He said if (Grealish) comes on I had to get nibbling in his ear,” O’Donnelly said. “But don’t be critical, be complimentary. So the full time he was on I was telling him how good looking he was and that I loved his calves!
“I was asking him how he get his hair like that. John said that if you tell him he was hopeless or to kick him really, really hard he gets up and gets back at you.
"So maybe that was the advantage against Jack Grealish the other night.
“I also noticed he doesn’t shave his calves. Most boys shave their legs as it’s good for the masseurs but Jack’s got massive calves and he doesn’t shave them.
“So I said to him they must be so big the fact that he doesn’t shave them and they still get spoken about!”
Scotland know they could secure qualification from the group with a win over Croatia on Tuesday.