MEMPHIS: Donald Young upset No. 2 seed John Isner 7-6 (5), 3-6, 7-6 (6) on Friday night in the quarter-finals at the Memphis Open for his first victory in four tries over the world's 23rd-ranked player.

Young reached his seventh career semi-final and second in Memphis by overcoming the big-serving American in the tiebreakers of a match that took 2 hours, 23 minutes.

"With him, it comes down to a couple points here and there, and I was able to get those today and I was able to hold my serve for the most part of the match and just defend well," Young said. "I'm happy to get through it. I don't know how it happened. I just stayed focused and battled."

Young will play fellow American Ryan Harrison on Saturday with the indoor tournament up for grabs with Isner having been the last seeded player left. Harrison beat Damir Dzumhur of Bosnia-Herzegovina 6-3, 6-4 in the late match.

Mikhail Kukushkin of Kazakhstan upset fourth-seeded Steve Johnson 6-0, 6-4 earlier Friday, needing only 70 minutes to advance to the semi-finals. Kukushkin will play Nikoloz Basilashvili of Georgia on Saturday. Basilashvili, who upset top-seeded Ivo Karlovic in the second round, reached his second straight ATP Tour semi-final by beating qualifier Matthew Ebden of Australia 7-6 (3), 6-4.

Isner took the first three matches against Young. This was their first match since Miami in 2014.

Young took advantage of Isner's mistakes to win the tiebreaker. While serving, Isner came to the net and hit a forehand into the net to drop to 4-3. Then he hit a forehand into the net on the next point. Young had three set points up 6-3 before Isner held his serve. Young then took the set when Isner hit another forehand into the net.

Isner finally converted on Young's ninth break point in the second set and then held serve to take the second set 6-3.

But Isner hurt himself in the third-set tiebreaker. He hit a backhand long before sending a forehand into the net. Then Isner hit a backhand long to fall behind 4-1. Young failed to convert on three match points up 6-3, then Isner hit another backhand into the net. After serving, Isner came to the net for Young's return and smacked it into the net for the final point.

"He's beaten me every other time we've played so I wanted to get at least one," Young said. "I'm just happy I was able to stay focused, come through, deal with a little tightness and still prevail. So I'm happy with the performance."

Johnson won his first career ATP title at Nottingham last summer and came into this event ranked 30th. Against Kukushkin, Johnson managed to save only one of the six break points he faced.

Basilashvili broke Ebden to finish off his match in 1 hour, 44 minutes.