The Lakers got smoked by the Toronto Raptors on Sunday night -- and LeBron James didn't exactly play great -- but he was still in the mood to party afterward.
TMZ Sports spotted James on the way into Diddy's 49th birthday party at Ysabel in West Hollywood ... where he celebrated with the likes of LL Cool J, Kourney Kardashian, Usher, Mary J Blige and Kid Capri.
James pulled up with his wife Savannah in his $340k Rolls Royce but made it clear he didn't wanna talk basketball.
Here's why ... Bron and the Lakers lost to the Raptors 121 to 107 .