The Warriors must keep the winning habit until the final game of the pool stages against Stade if they are to secure top spot - and give Percival the chance to upset the French giants again!
Percival was part of the Harlequins team that sent shockwaves through Europe when they defeated Stade 15-10 in the Heineken in December 2008 and he would relish a repeat.
"We have Bucharest first up and that is not a little trip or holiday for us - it's vital we get the right result," said Percival.
"We are not looking at it other than two big games, we want two bonus point wins and then we can be going over to Stade Francais next year with everything to play for.
"I've played at the Stade de France in front of 80,000 people and if you want to go over to France and have a big crunch match it would be against them.
"It's always a massive atmosphere in Paris and they are a top class team. But even up against superstars, you raise your game and it would be like playing an international for us.
"That is why you play rugby, to play games like that, so the focus is really on Bucharest to get the right results before Christmas."
Percival made his playing return against Exeter Chiefs last weekend and while the result did not go the way of the Warriors he was pleased to be back in the thick of the action.
He added: "It's awesome to be back playing. I had a point to prove after the boys had a fantastic win over Bath.
"It broke my heart watching the win and not being able to be part of it - it made me want to come back and put my marker down. I want to be in this team week in and week out and push us up the table.
"We are not losing by big margins, it is small margins and we look back and know we have probably got ourselves to blame rather than the opposition being a better team.
"It is our first season back in the Aviva Premiership and we will learn from it. We will be a better team for this and we must take massive positives from the Exeter game and that point."