Kokkinakis overcome early problems with his vision and a nightmare run of fluffed break-point chances to book a spot in the last four of the Adelaide International 2 on Thursday night with a 6-7 (7-5) 6-3 6-2 comeback win over fellow Australian Aleksandar Vukic.

The 25-year-old's reward is a shot at 2014 US Open champion and 2018 Australian Open runner-up Marin Cilic for a spot in the final.

World No.29 Cilic earlier secured his berth in the final four with a 6-4 2-6 6-3 win over American Tommy Paul.

Kokkinakis fell in the semi-finals to Gael Monfils in last week's Adelaide International 1, but he now has the chance to go all the way in the tournament's sequel.

After ousting power-serving American John Isner on Wednesday, Kokkinakis would have had an easy night against Vukic if it wasn't for his inability to convert his break point opportunities.

He was 0-11 until he finally secured a break late in the second set.

"Don't remind me, I was counting them to myself every time they were going by," Kokkinakis said during his on-court interview when asked about the missed break point opportunities.

"I felt like I could have won the first set 6-1 or 6-2.

"He was coming up with some good serves, I was being a little bit tentative, I was trying not to lose my marbles completely.

"And then, 2-1 in the second set, I was 0-11, I was really about to lose it.

"Thankfully I took one and eventually I let it go and started playing good tennis from the second onwards."

Kokkinakis had opportunities galore in the opening set, but he failed to convert any of his nine break-point chances.

Vukic created just one break point chance - which he couldn't convert - but he held his nerve during the tiebreak to secure the set in 65 minutes.

Kokkinakis couldn't see the ball properly at times, saying "I can't see the ball" at one stage of the tiebreak.

He requested eye drops from the physio during the break in a bid to clear his vision.

"My concentration was going. I felt really flat on energy," Kokkinakis said.

"I felt like I was losing the ball ... I was picking it up real late. I felt a little bit dizzy.

"I heard eye drops helped. It's actually the first time I've ever used them in a match. It cleared up my vision better than I thought.

"I'm happy. Maybe I'll give the physio a little cut (of my winnings)."

Kokkinakis' frustrations grew early in the second set as he blew his 10th and 11th break point opportunities.

He let out a loud celebration roar when he finally converted one to go 5-3 up in the second, and he reeled off eight of the final 10 games of the match to secure the victory in 2hr.13min.

Corentin Moutet and Arthur Rinderknech will face off in the other semi-final.

Australian Associated Press