Carlos Alcaraz’s 12-match winning streak was brought to an abrupt and unexpected halt at the Shanghai Masters as the third-seeded Spaniard lost in straight sets to Czech Tomas Machac.

Alcaraz, who helped Europe win the Laver Cup last month before going all the way in the China Open at the weekend as he defeated Jannik Sinner in the final, lost 7-6 (5) 7-5 in one hour and 55 minutes.

Machac, the 30th seed, is guaranteed his best result at Masters 1000 level after progressing to the semi-final, where he will meet world number one Sinner, who brushed aside Daniil Medvedev 6-1 6-4.

“I knew that the level of my tennis would be great because I am playing the best right now, for sure,” Machac said in quotes on the ATP Tour website.

“With these types of players, I have to play this level otherwise it’s (a) 6-2, 6-3 (defeat and) you go home, there is no other option. I am happy I managed to play like this for two sets.”

Machac came into this quarter-final contest with confidence having been deadlocked with Alcaraz at one-set all in last month’s Davis Cup, only to have to retire because of cramps.

“I knew that I had a chance (to win), but you never know, even with a set and 5-4 it’s still so far from winning the match,” Machac added.

“I played great tennis against him in the Davis Cup but there was this level (for) only one set. Today it was two, so it was enough.”

Sinner, meanwhile, claimed his seventh win in his last eight meetings against Medvedev. Having lost his first six matches against fifth seed Medvedev, the Italian tied their rivalry at seven wins apiece.

Medvedev, who required treatment on his shoulder midway through the second set, made 12 winners and 25 unforced errors, with his serve broken three times. Sinner faced – and saved – just one break point.

“I’m very happy how I handled this match” Sinner said after his triumph in one hour and 24 minutes. “It felt like he had a bit of shoulder pain and couldn’t hit his forehand as well as he wished to.

“Hopefully he can recover as fast as possible, but from my side it was a great match, a great battle, and let’s see what I can do now in the semi-finals.”