And whilst O'Shea admits they know their compatriots well from their battles in the English Premiership he believes their encounter in Europe will be completely different.
"We face a big challenge at the weekend but it's great to be back in the Heineken Cup - this is proper rugby," he said.
"Gloucester's a tough place to go but that's what you play rugby for.
"Even though we're familiar with Gloucester in the Premiership, there's the atmosphere that goes with the Heineken Cup at Kingsholm.
"They are a great side down there and they grow with the Kingsholm crowd. It was 26-19 to them down there in the league last season and we were held up over the line trying and draw the game so hopefully we'll go down and be competitive - and I think we will.
"It's nice to win matches because it keeps the feel-good factor but the record is an irrelevance, our next game is the most important. Winning breeds confidence, though. Maybe when you're in the midst of a tough game you find the mental strength to come out on top because the belief is there. We were tested big time against Connacht but we had the fortitude to come through. I'm delighted that we showed that sort of mental strength.