Yes - well actually watched the game in Perpignan then travelled Bcn to fly back - a couple of years ago. You could get bus, train or hire car between the two. We used car hire to Bcn airport and took bus to centre of Bcn.
If you're flying to Bcn then going to the match the same day I'd hire a car to Perpignan. Not sure of the frequency or speed of trains to Perpignan fromBcn.
I have flown into Barcelona a couple of times. I looked at trains but the times weren't great and the cost for train was more than hiring a car. I suppose it depends how many of you there are. I found the journey in the car pretty easy. Motorway all the way. We booked a hotel in perpignan for game day and ditched the car at the hotel. If i remember correctly you can do it in under an hour and half.