Muhammad Ali -- 'TEAM PACQUIAO'

"The Greatest" has picked a side in the fight of the century -- with Muhammad Ali's daughter telling TMZ Sports, "My dad is Team Pacquiao all the way!"

We spoke with Rasheda Ali -- who's very close with her dad -- and she tells us, "My dad really likes Manny. He's a huge fan of his."

"He knows Manny's a great fighter ... but it's more about what he does outside the ring. He's such a charitable person."

Rasheda says Manny and her father have been friends for years -- and he even came to Muhammad's 70th birthday party back in 2012.

As for Floyd Mayweather, Rasheda tells us her dad respects him as a fighter -- but says he and Muhammad are two VERY different people.

"My dad stood for things. Mayweather ... I don't think there's a comparison."

Unfortunately, Muhammad won't be attending the fight in Vegas ... but Rasheda says he wouldn't miss it for the world.

"There's no question he's going to order it. It takes my dad way back to when he was fighting."