French Open: Alexander Zverev's condition key to Thiem clash in Paris

Alexander Zverev might be mentally drained after three five-set matches in a row when he takes on Dominic Thiem in a much-anticipated French Open quarter-final clash on Tuesday.

German Zverev, 21, made his breakthrough into the last eight of a Grand Slam in Paris but it came at a cost, which might well be collected by Austrian Thiem who has had an easier run.

Second seed Zverev, who beat Thiem at the Madrid Masters last month, has spent 11 hours 56 minutes on the court and had to rally back from two sets to one down in his last three matches.

Thiem, 24, is expected to take his opponent into long rallies and make the contest last.

"I would think that if both players were fresh I would say that Zverev has the upper hand because a best-of-five would suit him, giving him time to figure things out," three-time Roland Garros champion Mats Wilander, Eurosport`s lead analyst in Paris, told Reuters.

"But since Zverev has already had to play three five-setters, Thiem has a pretty good chance."

Thiem has already beaten 10-time champion Rafa Nadal three times on clay and either he or Zverev could be a big threat to the Spaniard if they meet in the final.

While Zverev might have slightly more talent, it is seventh-seeded Thiem who holds the key to their encounter.

Make him run and make it last, Wilander, who lifted the Musketeers Cup in 1982, 1985 and 1988, advised the Austrian.

"If Thiem comes and makes the first hour, hour and a half really physical and does not miss too much, then I actually think in this situation, because of the circumstances, this is a good chance for him to beat Zverev," the Swede said.

"Zverev has time to recover physically but at some point, you get tired mentally.

He can be ready physically and also mentally when he comes onto the court, but again, the scoreboard dictates so much how you feel."

If the match drags on and Thiem manages to take the lead, the mountain will probably be too high for Zverev to climb this time.

"If I were Thiem I would be going like, `You know what Sascha, today we`re going to go for a run. It`s not going to be a sprint but a run and we`re going to go uphill for four hours.

If you beat me, in the end, you`re better than me, but I`m going to take you the whole way.` If he does that Thiem is the favorite," said Wilander.

Zverev believes his condition will be fine for another long encounter, however. "I`m expecting another five-set match. I`ll get myself ready for that," he said.