The 27-year old left Celtic in February when Mowbray was at the start of his short rein at Parkhead but now finds himself at a new club but with the same manager.
McDonald enjoyed some good form in the Championship under Gordon Strachan at the end of last season but has started this term relatively slow. He now finds himself in a three-way battle with Leroy Lita and Kris Boyd at the Riverside since Mowbray arrived in late October but says it is healthy to have competition and indicated that the presence of the new boss does not bother him.
"It's the way it is when you have a new manager who has new ideas and different ways of playing," McDonald told BBC Tees after scoring for Boro in their 2-2 draw with Hull City on the weekend.
"You've just got to bite your lip and get on with it, you keep working hard and see what comes of it.
"And if you get in the team, you look to score goals and show the manager you're worth your place and hopefully that was the case today.”