Carlos Alcaraz insisted he will face idol Rafael Nadal “at full strength” in the Six Kings Slam semi-finals after defeating Holger Rune 6-4 6-2.

The Spaniard grew into the competition and initially appeared to struggle to cope with the unevenness of the hard court in Riyadh before pulling away from his Danish opponent.

But Alcaraz stressed he would not take it lightly against the 38-year-old in Thursday night's semi-final, despite the close bond between the pair.

“I’ll give it my all,” said Alcaraz. “I’m not surprised that he’s training and working 100%, hitting the ball super hard and feeling the ball really well.”

“I'm not surprised at all because he's a player, a legend. It doesn't matter that he stayed away from tennis for three or four months. He will come back stronger than ever.”

“So I will try to play good tennis if I want to beat him, but I will do my best without fear.”

The winner of the Riyadh exhibition tournament will pocket a staggering £4.6 million, so there should be no doubt about Alcaraz's motives in beating his Olympic doubles partner.

Still, the world No. 2 stopped short of calling it a privilege to compete against his close friend and “idol” so close to his retirement.

“I grew up watching him. He was my idol and still is my idol. It's a shame that he has announced he will retire from tennis. He’s a really important person in my life, in my career,” Alcaraz said.

“He was one of the reasons why I wanted to become a professional tennis player, so it's pretty hard for everyone, including me, to know that he's going to retire from tennis.”

“So I don't know if it's a privilege to play against him again or if it will be difficult for me. But I'll try to enjoy being on the pitch with him again, but I think it's really difficult for everyone.”

Alcaraz, who revealed he had already met Nadal off the court in Riyadh, needed a late break of serve to win a hard-fought first set against Rune.

But once he found his rhythm, the Dane faltered in the second round as Alcaraz secured an immediate break before conceding just five points on his serve and ending the game.

Jannik Sinner underlined his qualification as world number 1 with a confident 6:0:6:3 victory over Daniil Medvedev in the quarterfinals of the Six Kings Slam.

With his semi-final victory at the Shanghai Masters, the Italian confirmed that he would end the calendar year at the top of the world rankings.

Medvedev was little more than a spectator in the first set, winning 15 of 46 points and only pushing Sinner to break point once.

With a game on the scoreboard at the start of the second set, the Russian had committed seven unforced errors, including two double faults.

The world No. 5 eventually became frustrated as he struggled to recover from a break from Sinner midway through the set.

Medvedev pushed his opponent to four break points while trailing 3-4, but threw his racket onto the court several times when the elusive break failed to materialize.

The 28-year-old's collapse came shortly before Sinner's fifth break of serve and was the final act of a decidedly one-sided battle.

And Sinner was impressed with his own performance given the short turnaround after his triumph in Shanghai.

“It was a very good performance considering I only arrived a few days ago, not even yet. And I only had one training session,” said Sinner.

“This is of course a very nice moment for me. I have worked very hard in my young career to reach this position and it is the result of many, many years of work.”

“That's what I love about my job as a tennis player. Now I can enjoy every moment.”