Alex de Minaur leads stunning Aussie comeback to book United Cup quarter-final spot

Alex de Minaur has led Australia into the United Cup quarter finals, winning his singles match before backing up in the mixed doubles decider against the Czech Republic.

The world No.6 kept Australia's hopes alive after recording a straight-sets win over Jakub Mensik and putting his hand up to play another match on the same night.

De Minaur wasn't originally scheduled to play in the doubles, but was a last-minute replacement for John-Patrick Smith and teamed up alongside Storm Hunter.

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It was a must-win scenario for de Minaur all night after teammate Maya Joint earlier lost to Barbora Krejcikova, but he was up to the task in the 6-4, 6-1 victory over Mensik and then backed it up with Hunter to defeat Miriam Skoch and Dalibor Svrcina 6-2, 6-X.

The tandem proved far too strong for their Czech rivals and the break in serve to put the Aussies ahead 4-2 in the second set was the moment both Hunter and de Minaur knew the writing was on the wall and so did the crowd at Ken Rosewall Arena.

The result pushes Australia through to the final eight teams in the tournament, where they are likely to face either Poland or Germany.

De Minaur was on fire early in his singles clash, breaking Mensik's serve in the first set and let out an audible "come on" on multiple occasions as a nod to Lleyton Hewitt.

He took the first set despite Mensik saving multiple set points as the Sydney crowd rallied behind the country's top-ranked player.

The Aussie tennis summer kicks off with the 2026 United Cup from Friday, January 2. Watch it live and free on Nine and 9Now.

The 26-year-old flew out of the gates in the second set as well, breaking Mensik again as the fans surged behind the Aussie, knowing the enormity of the situation.

De Minaur raced away in the second set, despite one magical tweener from Mensik, to send the three-leg United Cup showdown to a decider.

"He broke his opponent," Todd Woodbridge said on commentary.

"Jakub Mensik did not know where to go. That will be a very uplifting and confidence-boosting match for Alex."

Earlier in the day, Joint struggled in her return from illness at the United Cup, going down in straight sets to former world No.2 Barbora Krejcikova.

She was outgunned and outclassed by Krejcikova and went down 6-4, 6-1 in Sydney on Tuesday evening in the first leg of Australia's clash with the Czech Republic.

Krejcikova raced to a 4-1 lead in the opening set but started to wobble slightly, which allowed Joint to force a much tougher task for the two-time grand slam winner before the more experienced player eventually rallied back to clinch it.

The young gun was broken with her first service game in the second set and appeared to be struggling to keep up with Krejcikova, who took a two-game buffer.

"What you see with Maya today is due to her illness, she's sort of waning in and out of intensity," Andrea Petkovic said on commentary during the second set.

"When I saw her last year, she was so good at keeping that intensity high throughout the entire match and that's going to be the real challenge for her, to find that point-in point-out intensity because the energy levels must be lower than usual." 

Things continued to unravel for the 19-year-old, blowing an opportunity to hold serve and allowing Krejcikova to further assert her dominance.

"Joint is starting to find this really hard going now," Sam Smith said.

She managed to give the home fans a glimmer of hope when she finally held serve mid-way through the second set, but it wasn't enough to stop Krejcikova's dominance.

"Tough night for Maya Joint, I feel for her and it wasn't her best performance given the circumstances," Casey Dellacqua said after the match.

Co-commentator Smith noted it was "not really a reflection of her ability" due to illness.