By Joseph Santoliquito

Las Vegas, NV (CBS) — It’s a giddy time. The Eagles have won one game, a surprising victory, to open their season and to hear some of the talk swirling around Philadelphia and on its airwaves, the Eagles may never lose another game again.

But before we get too far ahead of ourselves, some gravity has to be applied.

The Eagles were magnificent the first 32 minutes in their 33-27 victory over the defending NFC East champion Washington Redskins. They ripped through Washington’s defense for 21 first downs in the first half, to just three for the ’Skins.

After a quirky incomplete pass call by the referees gave Washington a 7-0 lead, the Eagles promptly responded with 33 unanswered points. Anything the Eagles wanted to do, they did. They amassed 322 yards of total offense in the first half Monday day, cranking out 7.4 yards a play—and we’re 53 plays.

Washington was muddled, confused. Redskin defenders were heaving for air and grabbing oxygen masks when they came off the field. Everything expected from Kelly’s offense came to fruition.

Was that it, however? Was that what the Eagles could do, or was it a case of catching a very ill-prepared team completely off guard with a very rusty quarterback feeling his way back to NFL speed?

Because that Eagles team, the one that had thrown a jolt into the NFL, didn’t appear again Monday night.

Consider the drop off: The Eagles had five first downs the rest of the game, to Washington’s 22. The Birds gained just 121 yards in the second half. Save for a super play by Cary Williams, who batted down a Robert Griffin III pass intended for Aldrick Robinson on fourth-and-15 at the Eagles’ 42 with 6:48 to play, the Eagles could have lost.

And Kelly knows it.

It’s why after the game Kelly said, “We made some mistakes, coach included, but I think just the way they approached the game, the energy that they played with, if you play hard, you have a shot at winning in this league. I told our guys played really, really hard.”

Whether the Eagles can go another 15 games at this pace—which Kelly plans on hitting the accelerator even more—is a looming question.

Yes, what Kelly devised and what the Eagles executed blindsided Washington. But it was the Eagles heaving for air by the fourth quarter. It was the Birds than had run out of gas in the end, grabbing desperately to what they had built earlier.

Can they do it again this week against San Diego, and rejuvenate themselves once more four days later against Andy Reid’s Kansas City Chiefs?

That could be the most curious thing about this season. Do we know who the real Eagles are?

Joseph Santoliquito is a contributing sports blogger for CBS Philly.

Watch & Listen LIVE