The Hoops are awaiting the winner of Finland's HJK Helsinki and Iceland's KR (the Finns lead 7-0 after the first leg) for the opportunity to make the group stage proper.
Middlesbrough's McDonald feels it could be great for football in Scotland, after recent events with Rangers, for Celtic to try and emulate what they achieved when he was at the club with a Round of 16 berth in 2007/08.
"Celtic have fantastic players and I hope they get in to the Champions League and give Scottish football a positive after what's happened," McDonald said.
"With me having a big soft spot for Scottish football, I really want the game to turn the corner.
"Champions League goals and games are the highlights of your career - playing at that level against the best teams in the world is fantastic.