Andre Ward is fired up his good friend, Kevin Durant, will be ringside for his rematch with Sergey Kovalev ... telling TMZ Sports the NBA Finals MVP has been pushing him to dominate. 

Ward says he and KD are so close, they were texting back and forth during the NBA Finals -- sending pump-up messages to each other for their respective battles. 

Ward says he's not only inspired by his fellow Roc Nation athlete, but his presence alone at the fight will force him to up his game -- admitting he fights better in front of big celebrities. 

Kovalev has some famous friends too -- telling TMZ Sports some of the most famous Russian athletes on the planet will be in Vegas to support him ... but they gotta pay for their own damn tickets.