PARIS // Andy Murray believes he will be up against 'one of the toughest guys' in tennis when he faces David Ferrer in the French Open quarter-finals.
The Scot recovered from another bout of back pain to to beat Richard Gasquet and set up the last eight showdown with the Spaniard.
Murray has never beaten Ferrer on clay, and admitted after his 1-6, 6-4, 6-1, 6-2 defeat of Gasquet that his quarter-final opponent - and sometime training partner - will prove a test.
"I think he's one of the toughest guys to play on any surface," Murray said.
"He's number five in the world, and he's been there for a long time now. He's had a good clay court season so far.
"I've always found it tough against him on clay in matches and in practice. I train with him quite a lot, and I get on very well with him.
"We know each other's games very well, and he's one of the best players in the world on any surface, so it's going to be a tough match."
Ferrer has never made the semi-final stage at Roland Garros, whereas Murray made it to that round last year before being defeated in straight sets by Rafael Nadal.
To add extra spice to the match, Murray's former coach Alex Corretja is now close to Ferrer as Spain's Davis Cup coach - though Murray is not too concerned about him giving away any insights into his game.
"It will be up to who plays the better tennis on the day. I don't necessarily think that Alex will be able to help him a lot," he said.
Defending champion Nadal will face fellow Spaniard Nicolas Almagro in their quarter-final match, going into the round having lost just 19 games in four rounds.
Still, Nadal says he is wary of Almagro, who is on an eight-match winning streak on clay, having won the Nice tournament in the week before Paris.
"He has fantastic shots. His serve helps. He has a very good serve. First and second serve are fantastic.
"Then, after this serve, he's able to play aggressive. He's able to hit the ball in the right conditions, in a good position. It's very difficult to stop him.
"So my work has to be to put him in difficult positions, try to play long, try to play a little bit to the sides, to the angles, make him play a little bit more uncomfortable."
A win for Nadal would be his 50th at Roland Garros since he first appeared as an 18-year-old in 2005. His only defeat came against Sweden's Robin Söderling in a fourth-round match in 2009.
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