MELBOURNE - Alexander Zverev played his best tennis when it mattered most to down Tommy Paul 7-6(1) 7-6(0) 2-6 6-1 on Tuesday and reach his third Australian Open semifinal in five years, keeping alive his dream of finally landing a Grand Slam title.

The 27-year-old German was unable to find his peak level for much of a match played in the stifling afternoon heat on Rod Laver Arena but dominated his American opponent in tiebreaks to lock up the first two sets.

Paul bagged the third set but second seed Zverev upped his intensity to whip through the fourth and set up a meeting with the winner of the later blockbuster clash between Novak Djokovic and Carlos Alcaraz.

"To be honest, I should have been down two sets to love, he played better than me. I was not playing great," Zverev said after reaching his ninth Grand Slam semifinal, the most among active players who have not won a major.

"(Somehow) I'm up two sets to love and all of a sudden, I need only one more set, and the fourth set was definitely the best that I've played.

"I'm obviously extremely happy to be back in the semifinals."

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Paul, also 27, had beaten Zverev in their two previous meetings and worked assiduously to gain the upper hand in the first two sets only for the German to raise his game to drag him back into a dog fight.

The 2023 semifinalist converted his fourth break point to take a 6-5 lead in the opening set but Zverev returned the favor in the next game before racing away with the tiebreak 7-1.

Paul broke again early in the second set with a backhand pass as Zverev charged the net and this time he was able to consolidate for a 3-0 lead.

Zverev had break points at 4-2 and blew up at umpire Nacho Forcadell, who had already handed him a code violation for an audible obscenity, after a let was called mid-rally on a deuce point when a feather drifted down onto the court.

Paul held but a riled-up Zverev broke him to love on his next service game to put the set back on serve at 5-4. The German then fended off another break point to hold for 5-5 before denying the 12th seed a single point in the tiebreak.

Zverev gave up his opening service game in the third stanza and Paul doubled his advantage when he crushed a forehand winner for a 5-2 lead before holding to love to clinch the set.

It was a false dawn for the American, though, and the final set was a one-sided affair with Paul not getting on the board until he was 5-0 down, and that only after four deuces.

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"He did what he always does," said the American. "He picks up his level at the big moments, and my level unfortunately dropped in the big moments today."