Carlos Alcaraz likely just played his tennis idol Rafael Nadal for the last time in their professional careers during Thursday's semifinal match of the Six Kings Slam. Although the score makes it look like Alcaraz ran away with the match at 6-3, 6-3, the 21-year-old admitted he still had to play his best in order to beat the 22-time major champion.

Rafael Nadal, in his first match since announcing he would be retiring after the Davis Cup next month, lost 6-3, 6-3 to Carlos Alcaraz at the Six Kings Slam on Thursday.

The 38-year-old Nadal, who announced last week he would retire from tennis after the Davis Cup Finals in Malaga in November, lost 6-3, 6-3 to 21-year-old Alcaraz in the semi-finals of the Six Kings Slam event in Saudi Arabia.