The Association's MVP race is basically down to Harden vs. Giannis Antetokounmpo with only a handful of games left to play ... and Rip tells us he's giving the nod to the Bucks star for now.

And, why? The Detroit Pistons legend says he's gotta reward Giannis' win-loss record.

"You gotta give credit to Giannis, man. He's on the No. 1 team. He could be All-NBA on defense. So, right now, with Giannis being the best team, I might have to go with Giannis."

Antetokounmpo's Bucks are No. 1 in the East with a 59-20 record ... while Harden's Rockets sit at No. 3 in the West at 51-28.

But, Harden's numbers KILL Giannis' ... James is averaging almost NINE more points per game AND more assists and steals per contest too.