UNIONDALE, N.Y. -- Reilly Opelka edged top-seeded John Isner the same way he knocked his fellow American out of the Australian Open, winning a match full of tiebreakers Saturday night in a New York Open semifinal that set a record for combined aces in a three-set match.
Opelka fought off six match points in a marathon second set and went on to win 6-7 (8), 7-6 (14), 7-6 (4) to move within a victory of his first ATP title.
The 6-foot-11 Opelka and 6-10 Isner combined for 81 aces and there were no breaks of serve. Opelka hit 43 aces, Isner had 38 and each had only one double fault.
"I just competed for every point," Opelka said. "I served very well. I thought he served unbelievable, but he's the greatest server of all time, so kind of what I expected."
It was similar to their meeting in Melbourne, when Opelka beat the ninth-ranked Isner in a first-round match that went four tiebreakers.
"Essentially just, heads I win, tails I lose. It landed on tails I guess," Isner said.
Opelka will play Canadian Brayden Schnur, a qualifier who had never won a tour-level match before this week.
Schnur recovered after blowing a 3-0 lead and eventually the second set to beat American Sam Querrey 7-6 (7), 4-6, 6-3.
Schnur was the final alternate accepted into the tournament's qualifying draw and was nearly gone from Long Island quickly, eventually overcoming two match points to beat No. 3 seed Steve Johnson in the second round.
There was nothing quick about the second semifinal, which lasted 2 hours, 31 minutes and went well past the previous record of 71 aces, set earlier this year in a match between Nick Kyrgios and Ryan Harrison.
Isner was in good position to win in straight sets, taking a 3-1 lead in the tiebreaker when Opelka pushed a forehand long. But he wasted a chance to win the match on his serve, and Opelka then kept erasing the rest of the match points when he served.
"Both of us were serving ridiculously well, so it was always going to come down to that," Isner said. "I had match point on my serve, so that stings."
Isner had dropped two matches this season, part of a six-match skid dating to the end of last year, before winning his first two matches here in straight sets.
But he was stopped again by Opelka, who fell two aces shy of Ivo Karlovic's record for most aces in a three-set match.