Alexander Zverev lost his first match since securing the men's world number one ranking as he suffered a surprise defeat by Alex de Minaur in the semi-finals of the Vienna Open.

German top seed Zverev, who will replace Jannik Sinner at the summit of the men's rankings on Monday, lost 4-6 6-1 6-7 (4-7) to the Australian fifth seed.

Victory means 27-year-old De Minaur has leapfrogged Spain's Rafael Jodar in the race to qualify for the season-ending ATP Finals.

"Super proud with how I handled the situation," said De Minaur

"I played on my terms. I was going to go out swinging and playing the right type of tennis, and that's what made the difference today."

After losing the first set, Zverev overpowered De Minaur in the second before a hard-fought decider.

With neither player able to create a break point opportunity, it was De Minaur who held his nerve in the resulting tie-break as he wrapped up victory inside two hours and 30 minutes.

De Minaur will face Spanish second seed Carlos Alcaraz in the final after he beat Daniil Medvedev in straight sets.

The seven-time Grand Slam-winner secured a 6-4 7-6 (7-2) victory over the Russian third seed to reach his fifth final of the year.

The win extended Alcaraz's unbeaten run at ATP 500 events to 25 matches with the 23-year-old last suffering defeat at that level to Holger Rune at the Barcelona Open in April 2025.

De Minaur will be competing in his fourth final of the year with his sole title coming at the Rotterdam Open in February.