UFC star Paddy Pimblett is the co-main event for Conor McGregor's big return at UFC 329 ... but he tells TMZ Sports he's not satisfied with just that -- he wants a piece of Mystic Mac himself!!

We caught up with the Baddy ahead of his bout with Benoit Saint-Denis on July 11 ... and he explained he can't wait to get in the Octagon and back in the win column.

He's expecting a bloodbath -- they're both coming to scrap, not "sniff balls." Either that, or it'll be a quick finish with Pimblett's hand raised at the end, he said.

Pimblett suffered his first UFC loss against Justin Gaethje in January ... but when reflecting on that result, he admitted it must have been the Highlight's destiny to win, considering he went on to beat Ilia Topuria at the White House months later.

While he'd love another go with Gaethje, Pimblett understands he might have to work his way toward the belt -- and in the process, he could take on McGregor at 170 pounds ... which wouldn't require a weight cut.

Pimblett said it would be a showdown with the biggest fighter the UFC has ever seen ... meaning it would also be the most significant payday of his career.

There's more ... we also asked Pimblett if he's also keeping one eye on England in the FIFA World Cup -- it turns out he couldn't care less!!

Check out the full interview.