They love Rihanna, but still hate each other.

A festering beef between R&B singer Chris Brown and rapper Drake over their gorgeous ex-girlfriend exploded Thursday into a bloody, bottle-throwing melee inside a packed Manhattan club.

Drake, accompanied by a menacing 15-member entourage, incited the predawn brawl by rejecting Brown’s peace offering — a $2,000 bottle of Ace of Spades champagne — and sending back an incendiary note, police sources said.

“I’m still f—— Rihanna,” it read.

Once the note arrived, all hell broke loose at the table shared by Brown, his model-girlfriend Karrueche Tran and the rest of his entourage, sources said.

Five members of Drake’s posse peeled off their shirts as the fighting kicked into high gear with Brown’s overmatched group, a witness told police. The drama erupted just as the last song was playing.

Brown, 23, lost a chunk of flesh from his chin after he was reportedly punched in the face and cracked with a bottle.

Brown’s hulking bodyguard, Big Pat, was gushing blood after his shaved head was split open, while Brown’s tiny girlfriend and five innocent bystanders were bloodied by flying glass.

Bottles soared through the celebrity-studded crowd like glass grenades as the ruckus seemed to ignite instantaneously.

“I was sitting right next to Chris Brown after he sent Drake the bottle, his entourage approached him and they exchanged f yous,” Ingrid Gutierrez, a member of Brown’s entourage, told the Daily News. “Chris told them to bounce and all of a sudden someone tries to swing at Chris and mills and a lot of other guys in Drake’s entourage start throwing bottles at our table.”

Australian tourist Megan Cassidy, 23, collapsed to the floor after taking one directly to her head.

Police said Brown was trying to leave the club when Drake’s crew blocked his path.

Earlier, witnesses told police, two of the men approached Brown and asked, “What’s your problem with Drake?”

Other reports indicated Drake, a Lil Wayne protege from Toronto known for the hit “Best I Ever Had,” flipped the bird at Brown and his table before the smackdown started.

A 911 call at 4:16 a.m. summoned authorities to the basement club in SoHo to treat an unconscious patient — apparently the unfortunate Cassidy.

By then, both Brown and Drake had bolted from the wild scene on Vandam St. A video showed Brown stripping down to his waist before climbing into a waiting black SUV. Even the SUV was dripping blood.

“Get in the f—— truck!” a security guard screamed at Brown.

The chart-topping combatants released dueling statements denying any role in the brawl that left Club W.I.P. in shambles.

“Chris, Karrueche and his friends were victims of a brutal attack,” the Brown statement read. “They sustained several injuries.”

Brown, his girlfriend and his bodyguard spoke with detectives, said NYPD spokesman Paul Browne — and the singer pulled an apparent “stop snitching” move, insisting he never saw Drake inside the club.

But a witness told the Daily News the two were just a few tables apart in a VIP area, although Brown was ignoring Drake.

Drake’s rep said the hip-hop star “did not participate in any wrongdoing of any kind . . . He was on his way out of the club when the altercation began.”

Drake, according to some reports, was at Sin City, a strip club in the Bronx hours before the R&B beef. He was headed to Saratoga Thursday night for a concert with pal Meek Mill — his sidekick at the SoHo club. Mill tweeted Thursday that his name was linked to “some s— I wasn’t even really in!”

Browne said police planned to interview Drake “at a time more convenient for him and his attorney.”

Although no one was immediately charged, police were reviewing security video from the club and its ID entrance system — which documents the name of every guest.

Drake rolled in just 45 minutes before the fight began as one of the last arrivals at a birthday party for Javon Smith, manager of singer/songwriter Ne-Yo.

The mood shifted after Drake arrived — “a thug vibe,” the witness told The News. Prior to that, Brown was “low-key, keeping to himself, partying, dancing,” the witness said.

Brown posted a picture of his gashed chin on Twitter — accompanied by a series of insults directed at Drake and his crew.

“Lol … Throwing bottles like girls? #shameonya!” he wrote.

In another, he mocked Drake’s crew for “hiding in the bathroom” and standing “behind security.” The photo and tweets were later removed.

Hip-hip impresario Russell Simmons said he planned to speak with the two combatants about the free-for-all.

“I fight every single day to bury beefs, and I will call Drake and Chris to bury theirs,” he said in a statement.