Top seeds Carlos Alcaraz and Novak Djokovic heading for epic rematch in Cincinnati

The world number one fought back from a set down to confirm his place in the last four, where he will face Poland's Hubert Hurkacz.

Purcell, ranked 70th in the world, put the Wimbledon champion on the back foot with a series of quality shots to claim the first set 6-4 but the 20-year-old found his rhythm to take the second set 6-3.

Alcaraz broke immediately in the decider and had four break points in the third game of the set, but Purcell fought back to level at 2-2.

But the Spaniard broke to love in the ninth game and then saved a break point on his way to serving out the match.

"It was really tough," Alcaraz told ATP's website.

"It was tricky today. He served really well. I think he played well at the net, but I think I played well.

"I returned well on court and that was the key to getting the win today, to return very well and to focus."

Hurkacz powered past Alexei Popyrin 6-1 7-6 (8) to reach his first Cincinnati semi-final.

The world number 20 did not face a single break point, but did let a 6-1 lead slip in the tie-break before prevailing 10-8.

Later, world number two Novak Djokovic powered past Taylor Fritz 6-0 6-4 to set up a semi-final meeting with Alexander Zverev.

The Serbian had never lost to Fritz in six previous meetings and the result was no different the seventh time around, even if Djokovic was quick to downplay his 100% record after the match.

"Every match is a new match, a new challenge for both of us," he said. "We never faced each other here. Obviously being the No. 1 American, he gets a lot of crowd support.

"I just managed to get off the blocks really strong, played an almost perfect, flawless first set. Then I started off really poorly in the second and handed him the break, but from 2-4 down I played really four solid games in the second. Just overall a great performance."

Should Alcaraz and Djokovic both make it through their semi-final clashes, they will square off in yet another epic final, just over one month after their titanic battle to decide the Wimbledon trophy.

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