Top seed Juan Martin Del Potro saw off Kevin Anderson to book a semi-final showdown against Tommy Haas at the Citi Open in Washington.
Del Potro - looking to claim a third title in Washington - was in commanding form as he recorded a 7-6 (7/0) 6-3 victory over big-serving South African Anderson.
The Argentine was particularly impressive on his own delivery, not facing a single break point throughout the 1 hour 45 minute encounter.
Del Potro stepped up a gear to roll through the first-set tie-break without losing a point, part of a run that saw him win 15 points in a row - including six at the start of the second set which secured him the first break of the contest.
He would go on to close out the match with ease and now faces Haas, who he has beaten in each of their four previous encounters.
"It's a good opportunity to reach another final but I have to beat a very good player," Del Potro said afterwards. "He's playing good this season and he has got a lot of experience. I'll try to play like today or even better."
Of the victory over Anderson, he added: "I just tried to return his serves and find a way to break. In the second set I broke very early and played with more confidence the rest of the match."
Haas also advanced with a straight sets win, but was made to battle all the way before completing a 7-6 (7/5) 7-6 (7/3) victory over Bulgaria's Grigor Dimitrov.
A tight contest yielded not a single break of serve although it was Dimitrov who had more chances, securing five break points to Haas' one.
But he could not make the opportunities count and Haas ultimately progressed to secure a shot at Del Potro.
"Del Potro is one opponent I despise playing in many ways," the German said afterwards. "He has given me a lot of trouble. And he has been playing terrific tennis.
"It's going to be a challenge. I hope I can mix it up, play aggressive and not give him too many points."
Home favourite John Isner ensured there is still some American interest in the tournament as he came from a set down to beat Cyprus' Marcos Baghdatis.
In-form Isner claimed the seventh ATP Tour of his career in Atlanta last week and remains on course to make it back-to-back successes after a 6-7 (5/7) 6-4 6-4 win.
"I was pretty confident even though I lost the first set," Isner said. "I know I'm not going to win every tie-breaker. I was in a good rhythm and serving well.
"I wanted to make him beat me. I didn't want to lose my mind out there and I held it together pretty well over the last two sets."
Isner now faces Dmitry Tursunov in the last four after the Russian outlasted Australia's Marinko Matosevic 6-3 4-6 7-6 (7/4).