Hi once again, Kevin,
It's a bit of a hike from Parkhead back to city center, so you may want to consider taking a bus. However, if it's an afternoon match, and it's not raining, you could walk. It would give you the opportunity to see some of Glasgow that tourists don't normally see.
However, if you do take a bus back to your lodging, there are several that leave from (and return to) Buchanan Street bus station (which is almost directly across from George Square), and will drop you off near the stadium. You could also get off or get on the bus at the Glasgow Forge, which is a huge shopping center. Best thing to do would be to check with your lodging, or take a quick trip across to the bus station to check the schedules. Once again, don't sit upstairs on a double decker on match day!
You could also catch a taxi from the Forge. There is a taxi rank there. I think that the ASDA supermarket is open 24/7. Perhaps MC can confirm that.
Once again, enjoy the match!
p.s.: I'm not a Weegie, but it's my favourite city in Scotland, and I have many friends there.