Justin Timberlake on SNL -- Fires Back at Kanye West ... 'Suit & Tie' Doesn't Suck

It took a couple of weeks, but Justin Timberlake has finally responded to Kanye West's anti "Suit and Tie" rant, with a shot of his own on "SNL" last night.

It happened when JT was performing 'Suit and Tie' with Jay-Z last night -- the singer changed the lyrics from "Aww, s**t so sick, got a hit and picked up a habit" to "my hit's so sick got RAPPERS acting dramatic."

Not the strongest insult in the world ... but pretty obviously directed at Kanye West, who last month during a concert, dissed the song "I got love for Hov, but I ain't f--king with that 'Suit & Tie.'"

It ain't exactly Tupac vs. Biggie ... but gotta love the drama.