Kokkinakis scores upset win over Rublev

Thanasi Kokkinakis has sent his home-city fans into raptures with a rousing win over top seed Andrey Rublev to keep his Adelaide International 2 title defence very much on track.

Kokkinakis overcame an explosive first-set exchange with the chair umpire and the loss of the second set to upset the world No.6 with a sublime serving display on Wednesday night.

The South Australian crowd favourite rocketed down 17 aces to storm into the quarter-finals with a 6-4 3-6 6-3 win before a sellout crowd at Memorial Drive.

"It's a big part of my game. If I'm serving well, I feel like I have a chance to beat a lot of guys," a jubilant Kokkinakis said.

Under huge pressure to defend the rankings points from his winning his maiden ATP Tour title last year in birthplace, Kokkinakis is set to at least remain in the top 100 after making the quarter-finals once again at the final Australian Open lead-up event.

"I've had my best memories on this court," he said.

"Last year was an incredible feeling, something that you only dream of as a kid.

"To play in front on you guys in this atmosphere every night is incredible. Thank you.

"He hits the shit out of the ball. He's a hell of a player, doing big things already and I'm stoked I got one of my biggest wins in front of you guys.

"So that's awesome."

Kokkinakis will play Miomir Kecmanovic for a place in the last four after the Serb eliminated fellow Australian Jason Kubler 5-7 7-6 (7-1) 6-4.

Compatriot John Millman will turn his attention to an Australian Open wildcard crack after bowing out earlier in the second round on Wednesday.

The 33-year-old, who had a rough year on tour in 2022, was ousted 6-3 6-3 by world No.32 Alejandro Davidovich Fokina.

Millman, ranked No.148 in the world, had battled through qualifying to reach the main draw of Adelaide and knocked off world No.38 Albert Ramos-Vinolas, another Spaniard, in the first round.

He vented his frustration at the chair umpire after Davidovich Fokina won the first set following a line-call challenge.

Davidovich Fokina successfully challenged a shot by Millman that was originally called in.

Millman thought his opponent, who played and missed the next shot, took too long to challenge.

"He goes for the winner, misses it and then says challenge. That's where you have to go 'no, it's too late'," Millman told the umpire.

He responded by breaking in the opening game of the second set but Davidovich Fokina broke straight back and won the next three games.

Millman, who notched a win over Roger Federer at the 2018 US Open and has been as high as No.33 in the world, dropped down the rankings last season after suffering a bizarre eye injury in Mexico.

Davidovich Fokina will meet fourth seed Roberto Bautista Agut in the quarter-finals after his fellow Spaniard eliminated Dutchman Robin Hasse 6-3 3-6 6-3.