Andrey Rublev grew so frustrated during a 7-5, 6-2 loss to Carlos Alcaraz at the ATP Finals on Wednesday that he repeatedly hit himself with his racket — so hard that he bloodied his left knee.

Rublev had already slammed his racket to the ground during the opening game of the second set. Then when the Russian missed a shot to hand Alcaraz a break, he started beating himself as he walked to his chair and then used a towel to wipe the blood off.

Blood continued to trickle down Rublev's leg as he played on and he eventually called a trainer for treatment.

“It’s OK,” Rublev said of his knee. “I get disappointed and couldn’t manage.”

The second-ranked Alcaraz, a 20-year-old Spaniard who is already a two-time Grand Slam champion, ended an uncharacteristic three-match losing streak following defeats to Grigor Dimitrov in Shanghai, Roman Safiullin in Paris and Alexander Zverev in his debut match in Turin.

“I played such a great level,” Alcaraz said.

While Rublev was virtually eliminated after losing both of his opening matches, Alcaraz boosted his chances of advancing from the round robin stage at the season-ending event for the year’s top eight players.

Alcaraz will next face Daniil Medvedev, who secured his spot in the semifinals with a 7-6 (7), 6-4 win over Zverev.

“The key against Medvedev is to play a perfect match — tactically,” Alcaraz said.

Jannik Sinner leads the green group with two wins following his victory over Novak Djokovic on Tuesday.

The top two finishers in each four-man group advance to the semifinals.

In a first career meeting, it was a tight first set until Alcaraz broke for a 6-5 lead. Then Rublev was left fuming when the opening point of the next game had to be replayed after his shot was called wide. The call was overturned on review after it was shown that the shot had landed on the line.

Rublev called it an “unlucky call.”

“But it’s part of the sport,” he said. “It happens every match. ... Just happen that it was important (point).”

In the next game, Rublev bloodied himself.

As the second set wore on, Alcaraz began producing one highlight after another. Like when he hit a forehand cross-court passing shot as he was in the process of falling down. Or when he pulled off a backhand winner down the line from far off court on the run a couple of games later.

Alcaraz missed last year’s ATP Finals because of an abdominal injury.

MEDVEDEV SOLID

Medvedev saved two set points in the opening set as Zverev was shaky on the big points at the end of both sets.

“Very tough match mentally. I’m happy that I was able to regroup,” Medvedev said. “The ending of both sets was very tight.”

Medvedev, the 2020 champion, improved to 11-7 in his career against Zverev and has now won five of their six meetings this year.

Medvedev also beat Rublev in straight sets in his opening match.

Zverev has had off-court issues recently after a German court issued a penalty order against him after allegations he caused bodily harm to a woman. Zverev has disputed the allegations and is contesting the penalty order.