Carlos Alcaraz is playing on at the Madrid Open…

The 19-year-old Spanish tennis player and defending champion overcame a tough test from Karen Khachanov on Wednesday, rallying late in the second set for a hard-fought 6-4, 7-5 win that set up a semifinal against Borna Coric.

It was Alcaraz’s 150th tour-level match, and his 117th victory to leave him with a winning percentage (78%) currently better than the likes of Pete Sampras, Boris Becker and Andre Agassi.

“My dream in tennis right now is to become one of the best tennis players in history,” Alcaraz said. “I know that this is a big dream, (it) probably is too big. But in this world, you have to dream big and you have to think big, as well. I want to be part of the the best tennis players in history. And I will work for it.”

Alcaraz was down 4-1 and 5-2 in the final set before winning the final five games to secure his fourth straight-set victory in Madrid.

The top-seeded Spaniard improved to 27-2 this year, having dropped only one set in his last 19 victories. He will be playing in his third Masters 1000 semifinals of the season.

“I knew I had to keep fighting no matter what,” Alcaraz said. “I had to stay strong because I knew that I would have my opportunities, and gladly I took advantage of the first one that I had to close out the match.”

Alcaraz converted on his first match point after the 10th-seeded Khachanov had taken control of the second set with an early break. The Russian had two break opportunities to go up 5-1 before Alcaraz rallied for the victory. The Spaniard, who finished with 31 winners, had converted on his first break opportunity to go up 4-3 and win the first set.

Alcaraz had cruised past last year’s runner-up Alexander Zverev in the previous round, while Khachanov – a semifinalist at the Australian Open this year and at the U.S. Open last year – had beaten fifth-seeded Andrey Rublev.

Alcaraz is trying to become the first player this season to win two Masters 1000 titles, after having already lifted the trophy in Indian Wells. He successfully defended his title in Barcelona and also won in Buenos Aires.

If Alcaraz wins the title again in Madrid, he will regain the No. 1 spot in the world rankings if he plays at least one match in Rome.