Delray Beach - Juan Martin del Potro never faced a break point and eliminated defending champion Sam Querrey 7-5, 7-5 on Friday night to reach the Delray Beach Open semi-finals.
Del Potro, the 2009 US Open champion, overcame 16 aces by Querrey, who was seeded fourth.
On Saturday, Del Potro will take on No 1-seeded Milos Raonic for a berth in the final. Raonic edged Kyle Edmund 4-6, 6-3, 6-4.
Raonic and Del Potro are two of the biggest hitters on tour and have split two past matches against each other - but they have not faced off since 2013.
On the other half of the draw, Jack Sock moved into the semi-finals by beating Steve Johnson 6-4, 7-6 (7/4) in an all-American match-up.
Sock will play yet another American next: Donald Young, who didn't even need to play a point to get to the semi-finals. Young's quarter-final opponent, Steve Darcis, withdrew from the tournament, citing personal reasons.
The third-seeded Sock is the only player remaining in the hard-court event who has not dropped a set as he seeks his second title of 2017, third of his career.
Young has never won an ATP title. Sock is 2-0 against Young.