MELBOURNE — Novak Djokovic had a perfect record in Australian Open semifinals, and he was playing almost flawless tennis to protect it.

It didn't matter that across the net was Aslan Karatsev, a 114th-ranked, 27-year-old Russian who had come through qualifying to make his debut in a Grand Slam tournament after nine failed attempts.

Djokovic made only one unforced error in more than 50 minutes.

It was tight for the first seven games — before Djokovic reeled off eight straight points to win the first set — and again when Karatsev went on an all-or-nothing roll late in the second set.

Sensing a shift in support for the underdog — there was a loud, vocal crowd at Rod Laver Arena after a five-day span when fans were barred during a local COVID-19 outbreak — Djokovic moved up a gear and finished off his opponent 6-3, 6-4, 6-2.

He's now 9-0 in semifinals at the season-opening major, and one win from a ninth Australian title.

"The more I win, the better I feel coming back," the top-ranked Djokovic said. "The love affair continues."

Djokovic will have a day off Friday when No. 4 Daniil Medvedev and No. 5 Stefanos Tsitsipas, who is coming off a five-set win over Rafael Nadal, meet in the other semifinal. He said he'd have a rest and get the popcorn ready to watch and see who he gets to face in Sunday's final.

Given his past success in Melbourne, Djokovic should feel confident going into another championship match. He already owns an all-time record eight Australian titles, and he's aiming for an 18th major title, which would reduce the gap to Roger Federer and Nadal, who share the men's record at 20.

The 33-year-old Serb also is aiming to be only the second man to win nine or more titles at one of the four Grand Slams. Nadal has 13 at Roland Garros. Djokovic, in Australia, and Federer, with eight at Wimbledon, currently share second place.

"Recovery is the priority right now," Djokovic said. "I've had enough match play, enough practice.

"Right now it's just gathering all the necessary energy for the most important match of the Australian Open."

Djokovic has played and beaten the likes of Federer — four times — Andy Murray and Stan Wawrinka in the semifinals at Melbourne Park and was bringing that kind of game against Karatsev right up until he was serving for the second set.

Then the Russian qualifier lifted his game, as he did in wins over three seeded players as he became the first man in the professional era to reach the semifinals in his debut at a major.

After a difficult hold in the seventh game, Karatsev broke Djokovic's serve for the first time in the match and then narrowed the gap to 5-4.

Djokovic regathered his composure to earn two set points but again got tight, losing them with a forehand long and a netted attempted drop shot at the end of a 32-shot exchange.

He had to save break points before getting another go. So when Karatsev shanked a forehand, Djokovic leaped as he punched the air and went back to his changeover chair yelling, "Yeah, Yeah, Yeah."

The crowd was back on his side, chanting his nickname: "Nole, Nole, Nole, Nole."

He broke to open the third set and again twice more to finish off.

After the win, Djokovic said Karatsev deserved plenty of praise for his amazing major breakthrough. Karatsev will move into the Top 50 for the first time next week, meaning he won't have to go through qualifying for the majors.

"It's given me more confidence — I've started to believe more," Karatsev said of his run.

The biggest thing he's learned in Melbourne, he added, is "that I can play with everyone — to be there, to compete with everyone."

And that goes right to the top.

Djokovic has been bothered by an abdominal muscle problem since the third round. He initially said it was a tear, but has since refused to talk about the details until after the tournament.

After his win over Karatsev, he said it's "the best as I've felt the entire tournament."

"I felt great. I could swing through the ball. No pain. Best match so far," Djokovic said. "It came at the right time. I'm thrilled to feel this way."