"We have had a pretty relaxed week," he said.
"We have had a tough season with only one week off before now, so to have this downtime and to rest and relax is ideal preparation for us.
"Of course we would rather be playing in the play-off semi-finals this weekend, but we aren't and we must do everything we can to win the Amlin so this week off has come at a good time.
"It's been a long season and the players are carrying knocks, so now its about getting them right and ready and we should have a full squad to pick from."
Harlequins' opponents at the Cardiff City Stadium are Michael Cheika's Stade Francais and whilst the French side may not have performed as well as they wished in the Top 14 this season, O'Shea is fully aware of threat they pose.
"They are an outstanding side and we know its going to be a tough game," he added.
"Their side is packed with stars and its going to be a great final.
"They are a formidable European outfit and you just have to look through their team list to see what they offer."