On the day in which he officially became a Great Quarterback, John Elway completed 12 of 22 passes for a measly 123 yards. He threw no touchdown passes and had one pass intercepted. But, carried along by 157 rushing yards from Terrell Davis, Elway’s Denver Broncos beat the Green Bay Packers, 31-24, in Super Bowl XXXII, snapping a III-Bowl streak of futility that had been laid at the feet of the Broncos’ quarterback.

Never mind that to that point in his career, Elway had passed for more than 48,000 yards, connected for 278 touchdowns, and had just 216 passes picked off. Never mind that he placed among the top five quarterbacks in NFL history for passes attempted and completed, yardage gained, and touchdown passes. Never mind that he was the architect of what had become known simply as The Drive, a miraculous series of 15 plays in which he moved the Broncos 98 yards to tie the 1986 AFC title game against the Cleveland Browns with 40 seconds left.

The hard truth was that two weeks after The Drive, Elway and the Broncos came up short against the Giants in Super Bowl XX, and a legend was born: Elway may have had Hall of Fame numbers, but he was a Big Game Loser.

It took him 12 years to shake the tag, and ironically enough, he did it in a game in which his play was anything but great. That, however, seems to be how we bestow true greatness on quarterbacks these days – by how they perform on Super Bowl Sunday, when everyone on earth, it seems, becomes not only a football fan, but a football expert.

This sort of thinking is ludicrous when you consider that Trent Dilfer, Brad Johnson, Jeff Hostetler, and Earl Morral have quarterbacked Super Bowl-winning teams, but Jim Kelly, Dan Marino and, so far, Peyton Manning have not. Conversely, had it not been for his leading of the Jets to their 16-7 upset over the Baltimore Colts in Super Bowl III, would Joe Namath be remembered for much more than a big contract, a fur coat, and a pair of bad knees?

By that standard, there is a heck of a lot more at stake this Super Bowl Sunday for Donovan McNabb of the Philadelphia Eagles than there is for New England’s Tom Brady, who has already stamped his ticket for greatness by dint of two Super Bowl victories.

Brady has been named the MVP in both those Super Bowls, putting him on a par with Bart Starr and Terry Bradshaw and perhaps, a mere 60 minutes of football behind the sainted Joe Montana, who won three. A mere four years into his NFL career, the Patriots’ QB has already started building his Hall of Fame credentials – projected over 16 seasons, his numbers so far match any quarterback who has ever played the game, including Elway and another celebrated “loser,” Dan Marino.

Marino, of course, is the all-time leader in just about every passing category the league measures, and until this season, holder of the NFL’s equivalent of 61 home runs, the single-season record for touchdown passes, 48, eclipsed by Peyton Manning’s 49. But in his only Super Bowl appearance, Marino was out-dueled by Montana, and consequently has been sentenced to a lifetime in a purgatory no quarterback wants to wind up in.

As recently as last week, Marino’s Super Bowl XIX “failure” – 29-for-50, 318 yards, a TD, and two INTs in a 38-16 Miami loss to the 49ers – was brought up on the set of an NFL pre-game show by Cris Collinsworth, who was trying to compare Marino favorably to Peyton Manning. Halfway through Collinsworth’s sentence, however, Marino stopped listening and began glaring. It is likely that 30 years from now, when someone brings up Super Bowl XIX in his presence, Dan Marino will still stop listening and start glaring.

One can only hope the same fate does not await McNabb, who through five seasons has posted Elway/Marino-like numbers while leading his team to devastating defeat in three consecutive NFC title games before finally breaking through this year against the Atlanta Falcons.

McNabb has shown remarkable athleticism and versatility – early in his career, he was considered more of a running threat than a passing threat – and unsurpassed courage, as on the day when he broke his ankle on the third play of a game but stayed in. Anchored to the pocket, he wound up throwing four touchdown passes. This year, McNabb proved himself to be one of the NFL’s most complete signal-callers in the NFL – with or without Terrell Owens.

Still, his Eagles have yet to win the Big One, which means that to a lot of people, Donovan McNabb still has a lot to prove. Like Marino, this may be McNabb’s one and only trip to the Super Bowl. Or, like Elway, he may have to suffer through a series of Super Blowouts before finally convincing the millions of part-time football fans who watch only on Super Sunday of what the rest of the NFL has known all along.

That greatness is built over the course of an NFL career, not just on the last Sunday of any given season.

Mr. Matthews is the host of the “Wally and the Keeg” sports talk show, heard Monday-Friday from 10 a.m.-1 p.m. on 1050 ESPN radio.