Ja Rule Guarantees Giants Will Make Super Bowl, 'I Said It First!'

... 'I Said It First!'

Did you know Ja Rule is a huge NY Giants fan?? Neither did we ... but it's true -- and he's guaranteeing his favorite squad will run through the NFC this season!!

"G-Men going all the way this year," he tells TMZ Sports. "We're going to the Bowl! I said it first!"

The rapper was leaving Palace Hotel in NYC when he made the bold prediction ... and his thoughts on the Giants didn't end there.

Ja also had some advice for Pat Shurmur on how to handle Saquon Barkley the rest of this preseason ... telling us it's best for the team if the rookie doesn't see the field again until week 1!!