BRISBANE, Australia (AFP) — Former world No. 1 Novak Djokovic’s Australian Open preparations suffered a major blow Friday as he was bundled out of the Brisbane International by towering American Reilly Opelka.

The 6-foot-11 Opelka served magnificently and returned just as well to stun the 24-time Grand Slam winner 7-6 (8/6), 6-3.

Djokovic had gone into the tournament insisting that at 37 he still had the game to trouble the younger players.

But Opelka, 27, a former world No. 17 who was out of the game for almost two years from 2022-2024 following hip and wrist surgeries, dominated the Serbian and wrapped up a comfortable win in an hour and 40 minutes.

Opelka came back to the sport in July last year but showed his serve has lost none of its potency in his time away.

He served 16 aces and only faced one break point throughout the match.

“He’s the greatest player ever,” Opelka said of Djokovic.

“The reality is we have nothing to lose coming in against him. You end up playing more freely and you take a lot more risks because it’s your only chance of beating him.”

“It’s tough for him, because you get guys like me who are going to roll the dice, and on a day like this things go my way, and that’s how it worked out.”

Opelka now faces another huge server in the semifinals, rising French star Giovanni Mpetshi Perricard, who made it 75 aces in three matches as he beat Czech player Jakub Mensik, 7-5, 7-6 (7/5).

The second semi-final will see defending champion and second seed Grigor Dimitrov up against another Czech, Jiri Lehecka.

In the women’s semi-finals, world number one Aryna Sabalenka overpowered Marie Bouzkova in straight sets.

Sabalenka, who has won the last two titles at the Grand Slam in Melbourne, beat the Czech player 6-3, 6-4 in a tough match lasting 1hr 45mins.

She now plays Russian teenager Mirra Andreeva, who defeated Tunisia’s Ons Jabeur 6-4, 7-6 (7/2).

The 17-year-old Andreeva showcased her rich potential by defeating former world number two Jabeur in a high-quality encounter.

Jabeur was runner-up at Wimbledon in 2022 and 2023 but has been out of action since August with a shoulder injury.

Andreeva was able to deal with the tricky shotmaking of Jabeur, breaking her once in the first set and then recovering from two breaks of her own serve in the second set to force a tiebreak.

She raced through the tiebreak to wrap up the match in 90 minutes.

“It was mentally hard to keep pushing and playing aggressively because we all know that she’s very good at playing games — drop shots, slices,” Andreeva said.

The second women’s semi-final will be between Russian qualifier Polina Kudermetova and Ukraine’s Anhelina Kalinina.

The Australian Open starts on 12 January.