Australian tennis star Jordan Thompson is into the final of the Los Cabos Open after delivering a stunning upset victory over No. 1 seed Alexander Zverev.

Thompson beat the German 7-5, 4-6, 7-6 (7-2) in a three hour, 40-minute thriller in Los Cabos to move one step closer to the $AUD1.3 million prize on offer for the tournament winner.

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The Aussie could have wrapped it up sooner, only to blow five match points in the 12th game of the third set.

However, Thompson would prevail over the world No. 6 in a tie-breaker he dominated.

“It was just a great match,” Thompson said.

“I competed until the end and I really don’t know what to say. I’m pretty tired.”

The victory over Zverev marks Thompson’s fourth win over a rival ranked in the top 10 as he secured a spot in his third ATP final.

Awaiting Thompson in the final is Norwegian star Casper Ruud, who rode a strong start to a 6-4, 7-6 (7-4) victory over defending champion Stefanos Tsitsipas.

Fourth-seeded Ruud didn’t lose a point on his first serve in the opening set, then had to save five set points in the second to seal a straight-sets victory.

“It was a really close match, all in all, especially the second set,” Ruud said.

“I was fortunate to save a few set points there and hold him off.

“I was just a bit lucky,” added Ruud, who faced set points in each of his last two service games but raced to a 4-0 lead in the tie-breaker and polished things off after one hour and 49 minutes.