Jannik Sinner admitted he was panicking on the inside after Novak Djokovic pushed him close in their Six Kings Slam semi-final.

There, he needed just two sets to win the title, but it was a different story in Riyadh as he required almost two and a half hours to defeat Djokovic 6-2 6-7(0) 6-4.

“Maybe from the outside [I seemed calm], but from the inside, there was a little bit [of panic],” Sinner told DAZN. “But it’s normal. This game can change so quickly.

“We played a final in Shanghai not so many days ago. I feel like we were both slightly tired, making a couple of mistakes, but just trying to stay there.”

Having rattled through his opening set against Medvedev 6-0 on Wednesday, Sinner enjoyed another fast start in the semi.

The Italian took the same amount of time, 27 minutes, to go within one set of the match against Djokovic and did not give the Serb a glimpse of a break.

Two love-holds and a pair of comfortable breaks were enough to see Sinner take control of the contest, though Djokovic managed to flex his serving muscles with a brace of love-holds of his own.

But Sinner appeared to struggle physically at the start of the second set, immediately surrendering his serve for the first time at the event.

He quickly regained composure, winning nine points in a row to back up a love-hold with a crucial love-break, and even Djokovic applauded when Sinner pulled off a sublime cross-court backhand inches from the net.

Both players struggled to find joy on the other’s serve from thereon in, as neither could take any game to deuce until the one-sided tie-break.

The Serb whitewashed Sinner 7-0 to level the match, extending his domination in tie-breaks this year with his 14th victory from 20 deciders.

And while the momentum was suddenly with Djokovic, Sinner was not to be denied in the hour-long third set.

The 23-year-old had to survive two break points at 3-2 down before fighting hard to seal consecutive breaks, which took the match away from the 24-time Grand Slam champion.