The hometown favourite again had Memorial Drive buzzing as he took down Sweden's Mikael Ymer on Friday, Kokkinakis prevailing 7-6 (11-9) 4-6 6-4 as the clock passed midnight.

The win was built on ferocious forehands and big serves and followed impressive victories over compatriot John Millman and fourth seed Frances Tiafoe.

The wildcard entrant - Kokkinakis is currently ranked No.171 in the world - is set to earn another to play at the Australian Open, where he first won as a 17-year-old in 2014 and last year pushed world No.4 Stefanos Tsitsipas to five sets in the second round.

But injuries - shoulder, pectoral, groin, knee, elbow and most recently the debilitating glandular fever - have conspired to stunt his career.

Only now at 25 is the South Australian enjoying a rare injury-free run, chasing his first ATP title and poised to do more damage in Melbourne later this month.

"I've no idea what time it is ... everyone going bunta (crazy) got me through that first set when I felt like I was going through a brick wall (in Ymer)," he said on court post-match.

"I don't need much motivation at the moment, but everyone's definitely helping.

"It's going to be a fun match (against Monfils); he brings his own energy, you don't know what you're getting at the other end.

"But when he's on .. he was one of my favourite players growing up."

The cool-headed Ymer provided a stern test, shrugging aside a dramatic tiebreak loss to force a deciding third set.

Kokkinakis broke immediately, though, and the local hope drew on his frenzied supporters as the clock struck midnight and a win loomed.

The Swede wasn't done though, finding another gear to break back.

Kokkinakis paired huge forehand and backhand winners to hold for 5-4 and then benefited from an Ymer double fault at 30-30 to break and close it out.

Former world No.6 Monfils, currently ranked 21, breezed into the final four, beating Tommy Paul 6-4 6-1 earlier on Friday.

Marin Cilic and Karen Khachanov will meet in the other semi-final.

Australian Associated Press