After Thiem double-faulted, Nadal leveled at 5-5 to the delight of the crowd.
Nadal also lost the world number one ranking to Roger Federer, despite the Swiss star not playing since mid-March.
Rafael Nadal suffered a shock 7-5, 6-3 defeat by Austrian Dominic Thiem in the Madrid Open quarterfinals on Friday, a result that means the Spaniard will lose the world No. 1 ranking. I lost the match, it was not my day. "If I had played normal I would have no chance", Thiem said. End of the story. He always had position to move around and to play a good shot, to strike the ball in a comfortable position for him. "Also when that happens it's because your opponent is doing really well". Dominic has a lot of potential.
Nadal paid tribute to Thiem for the way he played on Friday. Thiem ironically was the last man to beat Nadal on clay, in Rome last year, and is now the man who prevented him from going a year unbeaten, without dropping a set, on his favourite surface. Thiem ended Nadal's record of 50 sets won in a row on clay. Thiem then converted his second opportunity, ending Nadal's incredible run on clay and winning the match in just under two hours.
Only Novak Djokovic, Gaston Gaudio, and now Thiem have beaten Nadal at least three times on the slow stuff. "This is fantastic. So I had to play an extraordinary match, and that's what I did", said Thiem. I just want to congratulate him, that's all.
"I think from Shanghai till Monte-Carlo, I hadn't finished a single tournament".
Anderson leads Thiem 6-0 in their FedEx ATP Head2Head series, but they have not met on clay before.
Thiem will face sixth-seeded Kevin Anderson in the semifinals after he hit 15 aces to down Dusan Lajovic, 7-6 (3), 3-6, 6-3. It was very important I went into the match with a positive attitude, with an attitude to win.
Nadal pulled out of two tournaments last fall with injuries and then retired from his quarter-final match at the Australian Open in January because of a leg injury. He won the match 6-4,6-2 and will now be playing the victor of the match between Alexander Zverev and Denis Shapovalov. A borderline Masters 1000 specialist (two-time champion and recent Miami runner-up), the 21-year-old German booked his spot in the Madrid semis by avenging his Miami final loss to John Isner.