And with the added incentive of Heineken Cup on offer if Biarritz win at the Stoop, Harinordoquy is desperate to maintain the form that has seen them win six of their last eight games.
"It's a game with two goals for us," said Harinordoquy, who won the Grand Slam in 2002, 2004 and 2010.
"A win would give us another title and guarantee Heineken Cup qualification. It would also be a real accomplishment for a squad which has really suffered.
"We need to be selfish and think about ourselves so we can walk away from this difficult season with our heads held high.
"We are capable of the best and the worst, at the moment it seems like we are closer to our best, thankfully. If we want to win against Toulon we'll have to be patient. At the moment there is a lot of enthusiasm and euphoria and we are trying to finish things off too quickly.
"It's a final, anything can happen."