Chris Brown Topless Ballin' Before Fight with Drake

TMZ has obtained a photo of Chris Brown inside a NYC nightclub, taken seconds before he got clocked with a champagne bottle in a brawl with Drake's posse -- and he looks totally oblivious to the violence about to erupt.

In the photo, Chris is shirtless and holding a bottle of Ace of Spades champagne … surrounded by fans, friends -- and his bodyguard, Big Pat, who ended up hospitalized with a massive gash to his forehead after the brawl broke out in W.i.P. Nightclub early Thursday.

According to several eyewitnesses, Drake and Chris had been jawing at each other leading up to the brawl -- still, Chris doesn't look the least bit concerned in the photo.

We also obtained pics of Drake -- taken minutes earlier -- and rapper Juelz Santana is already standing next to him. We're told Juelz, Meek Mill, and Trav B all stepped up for Drake … and eventually tussled with Chris and his crew.

As TMZ first reported, NYPD officers have spoken to Chris, Drake and their attorneys. Neither has been named a suspect in the beatdown.

Last night, Rihanna hit the club scene in NYC -- but when she was asked about the Drake vs. Chris Brown brawl ... she bobbed and weaved like a prize fighter.