Daniil Medvedev will become the new world number one after Novak Djokovic was beaten by Jiri Vesely at the Dubai Tennis Championships.

Medvedev entered this week knowing victory at the Mexican Open would see him move to the top of the ATP rankings for the first time.

But the Russian was still waiting to play his quarter-final on Thursday when his ascension was confirmed courtesy of Djokovic's last-eight defeat in Dubai.

Djokovic, a seven-time year-end number one, had led the rankings for 86 consecutive weeks, boosting his record total to 361 weeks.

In his first tournament since missing the Australian Open, however, the five-time Dubai champion struggled to match 123rd-ranked Vesely and went down 6-4 7-6 (7-4).

Djokovic might have known what to expect, having lost his only prior meeting with Vesely in Monte Carlo in 2016.

The Serbian looked like getting to grips with his opponent at the start of the second set, applying pressure, but was then broken again and had to respond strongly to reach a tie-break.

Again, Vesely led, and Djokovic's match was summed up by a double-fault immediately after winning back the mini-break, allowing the Czech to prevail.

The victor hailed the end of Djokovic's reign, saying in his on-court interview: "It's great for tennis to have somebody new as world number one again.

"We all know Novak missed the Australian Open, but he's been such a champion, as world number one for 361 weeks.

"Tennis needs new number ones, new generations coming up, so I think it's just great."

As Vesely advances, second seed Andrey Rublev will fancy his chances of a second straight ATP Tour title after his win at the Open 13 Provence.

Rublev stretched his winning streak to seven matches in coming from behind to beat Mackenzie McDonald and make the semi-finals, where he will play Hubert Hurkacz, who defeated Jannik Sinner.