Del Potro scored a three-set win over Russian Youzhny in two hours and 7 minutes 6-1 3-6 6-3 in their first-round encounter.

Fresh from winning the Estoril Open two days ago, Del Potro quickly got into his stride here in Madrid and dominated Youzhny throughout the first set. However, in the fourth game of the second set the Argentine player needed treatment for a left hip injury that had originally occurred last week in Estoril.

Del Potro appeared slightly less mobile after treatment and went on to lose the second set with Youzhny capitalising and raising his own game.

In the third set the 13th-seeded Del Potro played through the injury and after managing to break the Youzhny serve in the fourth game, went on to victory and a place in the second round.

"I started to feel it in the semi-final in Estoril last week but I really want to play this tournament," said Del Potro. "I will be careful for my future - I am playing really well last week and this, but my first goal is to play healthy.

"I want to be safe this week so I don't want to risk my presentation in French Open."

Other first-round winners on Tuesday include sixth seed David Ferrer of Spain who survived a second set bagel against Adrian Mannarino to win in three - and Marcel Granollers who defeated last week's Munich champion Nikolay Davydenko in straight sets 7-5 6-2.

Andy Murray begins his campaign on Wednesday against Gilles Simon of France who defeated Croatian Ivan Ljubicic 7-5 7-6 (8-6).