Kyrgios with eyes on the ball in New York

Nick Kyrgios is not looking beyond his dangerous next opponent as a fourth-round US Open showdown with world No.1 Daniil Medvedev looms large.

NICK KYRGIOS.
NICK KYRGIOS. Picture: Emmanuel Wong/Getty Images

Nick Kyrgios has eyes only for JJ Wolf as a US Open blockbuster with world No.1 and defending champion Daniil Medvedev looms ever larger.

Kyrgios and Medvedev remain locked on a fourth-round collision course, each a win away from setting up the first heavyweight showdown of the tournament.

Kyrgios leads the Russian 3-1 head to head and upstaged the top seed only three weeks ago in Montreal.

If anyone can deny Medvedev back-to-back titles at Flushing Meadows, especially in Novak Djokovic's absence, it's the mercurial Kyrgios.

A last-16 clash on Sunday would be worthy of a final, with officials unhappy to lose either of the two big drawcards before the quarter-finals stage.

But Kyrgios isn't even looking beyond the third round, wary of the threat young gun Wolf poses.

The American was handed a wildcard into the Open after reaching his maiden ATP quarter-final last month in Washington, where Kyrgios won the title and Wolf knocked off grand slam semi-finalist Denis Shapovalov.

"He's got a massive game," Kyrgios said of the 23-year-old.

"I love the way he plays tennis. I love the fact that he has a big serve, tries to take it to the opposition. Serves big and plays big.

"With a game like that, he's going to have some great results. Obviously he seems like a hard worker, as well.

"I'm expecting an incredibly hard match. I know it's not going to be easy at all.

"I'm going into that probably the favourite, but I'm not going to take him lightly at all. I know he's beaten some great players."

Kyrgios plays Wolf on Friday (11am Saturday AEST) after his fellow Australian and one-time girlfriend Ajla Tomljanovic takes on the great Serena Williams in the first match of the bumper night session.

The stakes are high, with Tomljanovic hoping to make the second week in New York for the first time and Williams fighting desperately to fend off retirement once more in her emotion-charged farewell to tennis.

Williams is officially one defeat away from the end after the 23-times grand slam champion and big sister Venus lost in the first round of the doubles on Thursday night.

With big ambitions of her own, Tomljanovic knows there can be no room for sentiment when she confronts one of her childhood idols at Arthur Ashe Stadium.

"I've been a Serena fan since I was a kid. On Friday night I'll just be a competitor and I'll try my best to win," said the two-time Wimbledon quarter-finalist.

Alex de Minaur, the men's Aussie No.1 seemingly forever living in Kyrgios's shadow, is also chasing a fourth-round berth on Friday.

The world No.20 faces tough Spaniard Pablo Carreno Busta, the 12th seed, two-time US Open semi-finalist and newly crowned Montreal Masters champion.

"He's obviously playing some great tennis. A very tough match. It's going to be a battle," de Minaur said.

Big guns Kyrgios, de Minaur and Tomljanovic are Australia's last three standing in the singles after James Duckworth, Alexei Popyrin and Jason Kubler all lost second-round matches on Thursday.

Duckworth lost 6-3 6-2 4-6 6-4 to Brit Dan Evans, Popyrin succumbed 7-6 (7-3) 7-5 7-6 (8-6) to Argentina's world No.16 Diego Schwartzman and Kubler was equally gallant in a 7-6 (7-3) 7-5 7-6 (7-2) defeat to seeded American Frances Tiafoe.

Kyrgios also remains alive in the doubles after teaming with Thanasi Kokkinakis for a three-set first-round victory on Thursday after taking out his good mate in the singles event.

AUSSIES IN ACTION ON DAY FIVE OF THE US OPEN (PREFIX DENOTES SEEDING):

From 1am Saturday AEST

Men's singles, third round

18-Alex de Minaur v 12-Pablo Carreno Busta (ESP) - not before 7am

Nick Kyrgios v JJ Wolf (USA) - about 11am

Women's singles, third round

Ajla Tomljanovic v Serena Williams (USA) - 9am