Relentless Holger Rune topples six-time champ Novak Djokovic to reach Rome semifinals

WATCH: Novak Djokovic speaks with the media after his 2023 Rome Open fourth round win.

Before taking the court against Holger Rune, world No. 1 Novak Djokovic told press that his Internazionali BNL d’Italia quarterfinal opponent reminded him of himself: “Really fit physically, great defense, but also great counter-puncher.”

On Wednesday he got a taste of his own medicine, as Rune ultimately did to Djokovic what the Serb has done countless times to his own opponents. The 20-year-old overpowered Djokovic with a smart combination of speedy court coverage and relentless aggression, toppling the six-time Rome champion 6-2, 4-6, 6-2.

With the victory, No. 7 Rune booked a spot in his third career ATP Masters 1000 semifinal, after winning the title in Paris-Bercy in November and reaching the Monte Carlo final last month. He also takes a rare 2-1 lead against Djokovic in their head-to-head matchups.

"It's a good battle every time we play. I like to battle with him," Rune said in a post-match press conference. "He's a great player to play because he makes it so challenging for me, which I find that nice because I can really see where I have to improve, what is working.

"If it's working against Novak, it works against almost anybody. So I'm super happy with the win."

Never one to be intimidated by a big stage or legendary opponent, Rune was grinning ear to ear on Tuesday when he learned his next match would be another shot against the world No. 1.

He played like he meant it, too, across three sets in Rome, aided in part by an error-strewn performance from Djokovic who hit 13 unforced errors to Rune’s three in a bizarre first set.

“Now this one is kind of hard to explain,” said Tennis Channel’s Paul Annecone as he read through the first-set stats: Despite hitting just 30% of first serves (7/23), Rune seemed to be in complete control as he brushed aside two break points and broke Djokovic’s serve twice in turn.

Rune kept the pressure on into the second set, never allowing his opponent to settle into the contest—until a questionable line call from chair umpire Mohamed Lahyani rattled his composure.

Amid the confusion—Lahyani said the ball caught the line, while an unofficial Hawkeye replay showed it well out—the rain that had been threatening all day finally began to come down. It culminated in Djokovic’s first break of the match to go up 4-2, and gave the Rome crowd something to cheer for as the world No. 1’s comeback was officially on.

The rain would eventually suspend play for over an hour at 5-4, 30-0, and upon resumption Djokovic looked set to roar back as he calmly closed out the set. But Rune never went away, and the 20-year-old slammed the door shut as he took a double break lead in the third set.

Djokovic, who will drop back to world No. 2 next week, is now 20-4 on the season. He arrived in Rome after a few disappointing early exits in Monte Carlo and Banja Luka, and played down elbow injury concerns.

No. 7 seed Rune awaits the winner of No. 4 seed Casper Ruud and No. 24 Francisco Cerundolo, who will meet in the day’s second Rome semifinal.