Reilly Opelka beats John Isner in longest ever ATP Tour tie-break

Reilly Opelka has booked his place in the final of the Dallas Open courtesy of a record-breaking tie-break victory over John Isner.

Opelka triumphed in straight sets to set up a final showdown against Jenson Brooksby, overcoming Isner after a 46-point tie-breaker in the second set - the longest in ATP Tour history.

The final 26 points all went with serve as the big-hitters refused to yield, until Opelka finally took advantage of his eighth match point.

In all, the towering duo recorded 60 aces during the two-set match, which lasted just over two hours in total.

"I lost track. At one point it was 21-all. It's something I've never seen before," Opelka told reporters after the match.

"It just shows how clutch he is. If it was going to happen, it would have been in this match."

Neither player faced a single break point throughout the encounter, with both sets going to tie-breaks in Opelka's eventual 7-6[7] 7-6[22] triumph.