It ended in pain, tears and conflicted emotions between disappointment and ecstasy.
The fifth-year quarterback did not exit the field in Tiger Stadium under his own power. He had to be helped off by team trainers after this gruesome hit that left Mettenberger writhing in agony at the 38-yard line.
He did not return to the game after that hit and could only watch from the bench as Anthony Jennings, his backup, pulled off the most improbable of victories.
Les Miles couldn't give any specifics as to how serious an injury Mettenberger suffered, only that it was a knee injury and that he hopes he returns for LSU's bowl game. Miles said he told Mettenberger he should speak to the media to give one last message to the LSU fanbase.
Mettenberger refused because he might get "too emotional." And who could blame him?
The man whose career took him from Georgia to Butler Community College before finally finding a home in Baton Rouge gave every last bit of emotion he had during his three years at LSU. His rejuvenation under Cam Cameron put him near the top of NFL Draft boards.
But that kind of success meant little to Mettenberger. He simply wanted to win, and after suffering through the disappointments this year in Athens, Oxford and Tuscaloosa, it's obvious he wanted to get one last victory in Tiger Stadium.
It's too bad he couldn't be on the field to experience it.
"The guy I met is not the guy that we have now," Miles said. "He's so much more important to us as a team. Who he's been for this club, the leadership and how he's improved, how he's matured, I'm a big Zach Mettenberger fan."
Miles isn't the only one. All week his teammates were asked what kind of legacy Mettenberger would leave behind at LSU. Guys like Jarvis Landry and Odell Beckham said he'll be remembered as one of the greatest to ever put on the purple and gold.
He's certainly up there. Mettenberger's 3,082 passing yards this season trail only Rohan Davey (3,347 in 2001) and JaMarcus Russell (3,129 in 2006). But Mettenberger will tell you that's not important. He wants to be remembered for more.
How his legacy is ultimately written won't be known for many years. Perhaps he's got one last game left in him, and he can create a more appropriate final memory than what happened Friday.
Maybe he'll be seen as the first in a line of many great LSU quarterbacks under Cameron's tutelage, and after what Jennings accomplished against Arkansas, that doesn't seem all that far-fetched.
But the one thing he certainly won't be remembered for is quitting. He picked himself up after getting sacked three consecutive times in that loss to Tuscaloosa.
And even Friday he tried to walk himself off the field, even though the physical limitations of his mangled knee made that impossible.
Mettenberger did have enough though to lead one last alma mater. On his teammates shoulders with tears streaming down his face, he sang of those Golden Oaks and Broad Magnolias in front of the Golden Band from Tigerland.
And though his LSU career might have ended in sadness, the LSU faithful are lucky they got to call him their quarterback.