ACAPULCO, Mexico – Argentina’s Juan Martin del Potro dominated in the early going and then won a tight second set to defeat Austria’s Dominic Thiem 6-2, 7-6 (7) and advance to the semifinals of the Mexican Open.
In a battle of top-10 players late Thursday night in this Pacific resort city, Del Potro’s superiority from the baseline was the key as he won a lopsided opening set and jumped out to a 2-0 lead in the second.
The ninth-ranked Argentine stumbled, however, when trying to serve out the match at 6-2, 5-4, netting a backhand at 15-40 after the Austrian had stayed alive in the point with an outstanding defensive lob.
The set came down to a tiebreaker, in which Thiem grabbed leads on multiple occasions but was unable to consolidate them by winning key service points.
Serving at 6-5, the sixth-ranked Thiem missed his first serve and then made a backhand unforced error to squander his second set point.
Del Potro then proceeded to grab an 8-7 lead after the players struck three consecutive aces.
Down a match point, Thiem needed to win a service point but instead threw in a double fault at the worst possible moment; he challenged the line judge’s “out” call, but Hawk-Eye confirmed that it was correct.
With the win, Del Potro improved his career record against the Austrian to 4-0.
“It was a hard match. I’m tired. But I have a day of rest to face an even tougher opponent (late Friday night) in Alexander Zverev; it’s my first semifinal in Acapulco, and I’m looking forward to it,” Del Potro said afterward.
The Argentine won his only previous match against Zverev, a three-set victory at last season’s ATP World Tour Masters 1000 event in Shanghai.
The fifth-ranked Zverev (the No. 2 seed in Acapulco) advanced to the tournament’s final four with a comfortable 6-4, 6-1 victory Thursday evening over American Ryan Harrison.
Friday’s other men’s semifinal will pit American Jared Donaldson against big-serving South African Kevin Anderson, who fired 18 aces in a 7-6 (5), 6-4 quarterfinal victory over South Korea’s Hyeon Chung.
Donaldson advanced with an easy 6-3, 6-1 win over Spain’s Feliciano Lopez on Thursday afternoon.
The women’s singles semifinal line-up also is set, with third-seeded Australian Daria Gavrilova to take on seventh-seeded Ukrainian Lesia Tsurenko and Swedish qualifier Rebecca Peterson to meet Switzerland’s Stefanie Voegele on Friday.