Ugly scene during the UEFA Europa Conference League final on Wednesday ... soccer star Cristiano Biraghi was pelted with trash while on the field -- and one of the objects hit him so flush, it opened a gnarly wound on his head.
The incident happened during the first half of West Ham's heated tilt with Fiorentina at Fortuna Arena in Prague ... after Biraghi's Fiorentina squad was awarded a corner kick.
You can see in footage from the game's broadcast, West Ham supporters were so upset over the call -- they launched empty cups at Biraghi's head.
Initially, the 30-year-old defender was unnerved by the trash-throwing -- aiming some sarcastic claps back at the unruly fans -- but when he realized he was bleeding profusely from the back of his noggin, he sought out medical attention.
Thankfully, while the gash looked bad, he was able to put a bandage on it and continue.
Refs, though, did have to pause the game -- while a public address announcer urged fans to refrain from throwing objects on the pitch.
At halftime, BT Sport commentator and ex-soccer star Joe Cole ripped the supporters for "moronic behavior."
But, the two teams were able to come out for the second half despite everything that had gone down in the first 45 minutes ... and West Ham went on to win it, 2-1.