Russian tennis star Andrey Rublev had a catastrophic meltdown during his straight-set loss to Carlos Alcaraz in a group stage match of the ATP World Tour Finals on Wednesday.

Rublev appeared to be upset for most of the match, but after he missed a shot to hand Alcaraz a break, he really went off. Rublev started to beat himself with the racket as he walked to his chair and used a towel to wipe off the blood. A trainer had to be called over to help stop the bleeding.

CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM

Andrey Rublev busts his knee

Andrey Rublev receives medical attention during a 7-5, 6-2 loss to Carlos Alcaraz at the ATP World Tour Finals at the Pala Alpitour, in Turin, Italy, Wednesday, Nov. 15, 2023. (Marco Alpozzi/LaPresse via AP)

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

Alcaraz won the match 7-5, 6-2. Rublev suffered two losses in the group stage, losing in straight sets on Monday to Daniil Medvedev. He now faces off against Alexander Zverev on Friday.

RAFAEL NADAL ENDS DEBATE: DJOKOVIC IS THE GREATEST

Andrey Rublev upset

Andrey Rublev reacts in the Men's Singles Round Robin match against Carlos Alcaraz of Spain during day four of the Nitto ATP Finals at Pala Alpitour on Nov. 15, 2023 in Turin, Italy. (Shi Tang/Getty Images)

Andrey Rublev reacts

Russia's Andrey Rublev reacts during the singles tennis match against Spain's Carlos Alcaraz at the ATP World Tour Finals at the Pala Alpitour in Turin, Italy, Wednesday, Nov. 15, 2023. (AP Photo/Antonio Calanni)

It has been a tough season for the No. 5-ranked tennis player in the world. 

He lost in the quarterfinals of three of the four Grand Slam tournaments this season. He was ousted in the third round of the French Open. It was his fourth quarterfinal finish in the US Open.

TENNIS GREAT PETE SAMPRAS REVEALS WIFE BRIDGETTE WILSON'S CANCER DIAGNOSIS: 'EXCEPTIONALLY CHALLENGING TIME'

He last won a tournament back in July. He topped Casper Ruud in straight sets 7-6 (3), 6-0 at the Nordea Open to win the Bastad Trophy.

CLICK HERE TO GET THE FOX NEWS APP

As for Alcaraz, he won his second Grand Slam title back in July with a win at Wimbledon. He’s been ranked No. 2 in the world since September behind the dominant Novak Djokovic.

The Associated Press contributed to this report.