Madrid Open: Rafael Nadal Stunned by Alexander Zverev To Cast Cloud Over Roland Garros Bid

Rafael Nadal lost 6-4, 6-4 to Germany's Alexander Zverev in the Madrid Open quarter-finals on Friday, casting doubts over the Spaniard's form ahead of this month's French Open. Nadal has now fallen early in two clay-court Masters tournaments ahead of the Grand Slam in Paris, after going out in the Monte Carlo quarter-finals last month before winning in Barcelona. Even in Barcelona, however, Nadal needed to save a championship point to beat Stefanos Tsitsipas in the final. World number two Nadal is hoping to clinch a 14th Roland Garros title and record-setting 21st major in the French capital.

Zverev's impressive straights-set win at the Caja Magica earns him a meeting with Dominic Thiem in the Madrid semis, in what will be a repeat of last year's US Open final, which was won by Thiem.

After losing to world number eight Andrey Rublev in Monaco, Nadal was convincingly beaten by Zverev and the spotlight will be on the 34-year-old now in Rome next week, his last tournament before heading to Paris.

It started well for Nadal when he broke Zverev to love to lead 4-2 in the first set, Zverev serving a double fault to give away the first advantage.

But the world number five immediately hit back and then pulled away, four straight games clinching him the set.

A whipping forehand down the line put Zverev up another break midway through the second and while Nadal resisted more pressure in the seventh game to hold, Zverev served out an impressive victory after an hour and 44 minutes.

Thiem had earlier come from a set down to beat John Isner 3-6, 6-3, 6-4 and reach the last four.

The 36-year-old Isner has never been at his most comfortable on clay but he caught Thiem cold by breaking early to claim the opening set.

But Thiem ripped a forehand pass to open up a break opportunity at 3-2 in the second, which the Austrian took when Isner hit the net with a volley.

Thiem was reading Isner's serve better by the time the match went to a decider but it was not until 4-4 that he struck again, when he chased down three Isner volleys to serve for victory. He closed out the win in just under two hours.

"He's one of the best servers in history, especially here in the altitude, it bounces high and it's so difficult to return," said Thiem after reaching the semi-finals for the fourth successive time.

"To start with a break down is almost like losing the first set but I stayed focused, kept a good fighting spirit. Very few points decide that kind of game and that's how I turned things around in the second set."