Juan Martin del Potro and Dominic Thiem set up a mouthwatering quarter-final at the Mexican Open in Acapulco on Wednesday.
Del Potro's encounter with Spanish veteran David Ferrer was an arduous affair, with the Argentine eventually prevailing in almost two-and-a-half hours after Ferrer had levelled the contest at one set all.
Eventually, Del Potro came through 6-4 4-6 6-3 to set up his date with third seed Thiem, champion in Acapulco two years ago.
The Austrian eased past 18-year-old Canadian Denis Shapovalov, losing just five games in a routine victory that took the Austrian just 74 minutes.
"I'm very happy because everybody knows how good he can play and how dangerous he is," Thiem said.
"I was really on from the first point. Today was almost perfect."
Also in the bottom half of the draw second seed Alexander Zverev beat fellow German Peter Gojowczyk to set up a showdown with Ryan Harrison, who beat last week's Rio champion Diego Schwartzman in straight sets.
But all eyes will be on Thiem's clash with Del Potro, with the Argentine back inside the world's top 10 and the Austrian a huge threat on clay in the early months of the season - his success at this stage of the year has been the grounding for him reaching the ATP Finals.
In the top half of the draw, Feliciano Lopez beat Australian wild card Thanasi Kokkinakis in straight sets and will next face Jared Donaldson, while Korea's Hyeon Chung is through to a fourth quarter-final of the year.
Having won the NextGen Finals last year, Chung beat Novak Djokovic at the Australian Open, and his 6-3 6-1 victory over Ernesto Escobedo has him through to a last-eight date with fifth seed Kevin Anderson, who beat France's Adrian Mannarino.
Thursday's quarter-final action gets underway at 10pm on Sky Sports Arena and then Action and Main Event from midnight
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