Prior to today, the greatest day in Philadelphia sports history was Sunday, October 19, 1980. It was a day that began as this one did, with an astounding Eagles victory.

This one in 2009 -- Eagles 40, Giants 17 -- was borderline absurd. I mean, nobody saw this coming. This was a game for first place in the NFC East. This was a game between evenly-matched rivals. This was a game between a Giants team that had lost two straight games and an Eagles team that could make explosive plays but couldn’t really sustain anything on offense.

The suspicion -- and by that I mean, everybody’s suspicion -- was for a train wreck kind of a game, with both teams hitting each other in the head and staggering around, trying to hit on something. Playing without running back Brian Westbrook (concussion), their historic Giant-killer, and with an offense line that has been mix-and-match, and with a quarterback (Donovan McNabb) who hadn’t looked very sharp the last two games, it was hard to see the Eagles doing anything really methodical on offense.

So, of course, what happened was the Eagles’ defense put clamps on Giants quarterback Eli Manning, forced a bunch of turnovers and bad throws, and then absolutely sliced open the Giants’ defense with a handful of huge plays. Fullback Leonard Weaver had a 41-yard touchdown. Wide receiver DeSean Jackson had a 54-yarder. Rookie running back LeSean McCoy had a 66-yarder.

For the Giants, it was an astounding, breathtaking defeat. For the Eagles, it meant first place in the NFC East. And for anyone who was wandering around a Philadelphia newspaper office in 1980, as I was, it brought back memories.

Because on that October day in 1980, two great events took place: the Phillies won Game 5 of the World Series, putting them one win away from the franchise’s first World Championship, and the Eagles beat the Dallas Cowboys at Veterans Stadium in the first divisional showdown between rival teams, back when beating the Cowboys was still something of a rarity.

So, that day in the office, the debate raged: how to play the two huge events on the back page of the Daily News?

It really was a debate, too -- that is how big a win over Dallas was back then. (Remember, this was only months before the Eagles would beat the Cowboys in the NFC Championship Game and go to the Super Bowl.) Sports editor Mike Rathet, a big football guy, was actually considering playing the two games as a kind of co-lead for a while.

The World Series ultimately prevailed. As a consolation prize, The Eagles got what was known in the business as a “big tease” on the bottom of the back page, a bigger-than-usual box pointing readers to stories about the Eagles-Cowboys inside.

Twenty-nine years later, if you asked people about a “big tease,” they would probably think you were talking about Cole Hamels. Which is another matter.

On the latest, greatest day in Philadelphia sports history, the Eagles help up their end -- shockingly so.