McAfee -- who spent 8 seasons in the NFL, but is now a member of Smackdown's broadcast team -- fought Vince's protégé in his first-ever match in WWE.

The 34-year-old made a grand entrance flanked by Dallas Cowboys cheerleaders ... punting a football into the crowd on his way to the ring.

McAfee's entrance was only the beginning of what turned out to be a historical moment -- once Pat got in the ring to mix it up with Theory, it was clear he came to do more than just hold his own ... he came to win.

Pat attempted a series of high-risk maneuvers -- moves generally left to the pros -- including sticking a landing on his feet after Theory pushed him off the top rope.

McAfee regained his composure, sprang to the top rope, and delivered a massive superplex to Theory.

The WWE universe was in disbelief at what they witnessed ... especially since Pat attempted Jeff Hardy's signature "Swanton Bomb" in the same match.

McAfee rolled up Theory from behind  -- pinning him 1,2,3 -- but he wasn't done yet.

Vince then got in on the action ... and the 76-year-old challenged Pat to another match in front of the raucous crowd.

Theory blindsided Pat by attacking him from behind ... giving McMahon the upper hand in his impromptu bout with the commentator.

Vinny Mac got the best of Pat -- with help from Theory, of course -- and began celebrating, but the sounds of glass shattering went off ... and WWE legend Stone Cold Steve Austin made his way to the ring to kick some ass.

In vintage Austin fashion, the Texas Rattlesnake hit Theory with a Stone Cold stunner and hit Vince with a stunner, as well ... after sharing a beer with his old nemesis.

Steve asked Pat to join him in some celebratory beers for his incredible WM performance -- and the two chugged some cold ones before Stone Cold hit McAfee with a stunner of his own -- and Pat sold it well.