Tennis Star Andrey Rublev Bloodies Knee During Wild Temper Tantrum On Court

Tennis star Andrey Rublev is going to need some bandages for his knee for the next few days ... 'cause he bloodied himself during a wild temper tantrum in a match on Wednesday.

Rublev's explosion happened while he was going up against Carlos Alcaraz in the ATP Finals in Italy.

Rublev had been trying to go toe-to-toe with the tennis superstar ... but when Alcaraz got the better of him one too many times, Rublev snapped.

Check out video from the court ... the 26-year-old smashed his racket into his knee six straight times -- opening up a gash that required medical attention.

He was ultimately able to finish the match ... though he fell to Alcaraz, 7-5, 6-2.

Afterward, Rublev told reporters his knee was OK ... adding, "I get disappointed and couldn’t manage."