Maybe second most important, rookie running back Bryce Brown again looked like a revelation, running for 107 yards on 14 carries in the first half. By the end, Brown - who tallied 178 yards on 19 carries in his first start, last week against Carolina - had run for the second-most yards in Eagles history in back-to-back games, behind only Steve Van Buren. Brown finished with 169 yards on 24 carries, giving him 347 in his two starts. Van Buren had 379 in a pair of 1949 games.
Again, though, Brown undercut his brilliance with a critical fumble. This time he lost the ball on second-and-7, from the Eagles' 44, his team trailing 31-27, Dallas backup nose tackle Josh Brent knocking it out. Corner Morris Caliborne, the guy who took all those penalties in the previous meeting, picked up the ball and ran it 50 yards for a touchdown that settled any doubt about the outcome, with 3 minutes and 50 seconds remaining.
Eagles rookie Damaris Johnson broke loose for that long-awaited 98-yard touchdown punt return with 31 seconds left, but it only counted for six points, not 11.
"That was costly," coach Andy Reid said of the Eagles' only giveaway. Reid noted that Brown, 21, who barely saw the field in college, "is getting used to playing again," and has to remember to focus on ball security, particularly later in the game when he's tired.
"He was tryin' to get every stinkin' yard he possibly could, and when you're doing that, you gotta overemphasize it," Reid said. "He's a heckuva young player."
Foles said that Brown "ran hard all night. I was really proud of him."
"It's no excuses," Brown said. "It's a crucial moment, you've got to protect the ball."
At 3-9, Reid seems to have lost the capacity for outrage; asked about a secondary that has allowed a cumulative 142.4 passer rating the past six games, he said something about "young-guy mistakes." The two rookies, slot corner Brandon Boykin and linebacker Mychal Kendricks, are the only pass defenders who haven't played at least 3 years in the league.
"We've got to do a better job of challenging," Reid said, when asked about his hapless defense. The Cowboys' four touchdown drives all went at least 80 yards. Reid pointed out that the pass rush died in the second half, giving Tony Romo lots of extra time to find receivers.
Maybe the first clue this wasn't going to be quite as discouraging as much of what has transpired lately was when the first quarter somehow concluded with the Eagles ahead, 7-0. A little perspective: Going into Sunday night, the Birds had been outscored 75-17 in the first quarter this season.
But that was where we were, somehow, after Foles briskly marched the Eagles 66 yards in just five plays on the Birds' second drive of the night, helped by a 24-yard Brown run and then a 10-yard Brown cruise for the touchdown through a wide-open left side, the path cleared by Evan Mathis and King Dunlap.
Things were going so well, Reid even won a replay challenge, the review taking away what had been ruled a third-down completion to Jason Witten for a first down.
Brandon Graham, starting in place of released Jason Babin, was a revelation, Graham dominating Cowboys tackle Doug Free for a sack-and-a-half early. The Eagles stuck with a rigorous defensive-line rotation, which meant Graham didn't get as many chances to build on his success as he might have. He had 11/2 sacks on the season before Sunday night.
"Second half, everything kind of like died down a little bit," Graham said. "I feel like we were giving it the same effort. We couldn't make a play in big-time moments...we're professionals and we've got to go out there and make plays. We didn't make the plays we needed to make to win."
The Eagles took their biggest lead of the season - that's right, of the season - on a seven-play, 73-yard drive on which Brown reeled off a 39-yard run and Foles found Jeremy Maclin for 21 yards, before Brown took the ball the final 5 yards untouched up the middle. It was 14-3.
Of course, Foles, Brown and the offensive line finding strong traction didn't fix the defense. Witten was wide-open on a - stop me if you've heard this before - huge coverage bust between Kurt Coleman and Nnamdi Asomugha that took the ball from the Birds' 28 to their 1. DeMarco Murray, playing for the first time since suffering a foot sprain Oct.14, scored on the next snap.
But given 41 seconds left on the second-quarter clock, Foles drove the Eagles 58 yards in five plays for Alex Henery's 43-yard field goal at the first-half gun. Henery had the league's longest current streak at 20 successive field goals, and the Eagles had a 17-10 halftime lead.
The defense gave it back on the first series of the third quarter, Murray finding gaping holes in an Eagles unit that eventually allowed Romo to scramble back and forth forever before finding Dez Bryant for a 23-yard touchdown and a tie score.
Ah, but Foles was undeterred. Eleven plays, 80 yards, and his first touchdown pass in a game he has started - a 15-yard rope to Riley Cooper on third and 3, Cooper reaching through Brandon Carr for a strong touch. Red-zone target, anyone?
Reid said Foles changed the call at the line on that one, an impressive adjustment for someone so inexperienced.
At that point, the Birds were 3-for-3 in the red zone, and Foles had his first touchdown pass since right after he came in for concussed Mike Vick in the previous Eagles-Cowboys game, Nov.11.
The Cowboys got even after a replay review of a fourth-down spot, something that almost never works in the NFL. On this night, Jason Garrett got the call, and at the end of a 12-play, 80-yard drive, Miles Austin cruised past Coleman for a 27-yard touchdown catch and a tie game.
Foles brought the Eagles back down yet again, 54 yards, 10 plays for another 43-yard Henery field goal and a 27-24 lead with 9:51 left.
It took the Cowboys all of 4:16 to get the touchdown they needed to go ahead. As has so often been the case, especially since coordinator Todd Bowles took over for Juan Castillo, the pass coverage basically just disappeared. After the 6-yard TD pass to Bryant that made it 31-27, Tony Romo was 22-for-27 for 303 yards - 81 percent passing, and why would you ever run? His passer rating was 150.5, running the streak of plus-120 games for Eagles opponents to six, which accounts for every game they've played since Bowles replaced Castillo.
Bryant's go-ahead TD also meant the Eagles have given up 16 touchdowns and intercepted no passes the last six games, which feels historic. Among many other things.
Foles threw for a career-high 251 yards, completing 22 of 34 passes, with no interceptions for the second week in a row.
"I felt really comfortable," he said after more than doubling last week's 119 passing yards.
Reid said he wanted to give Foles more shots downfield this week. Tight end Brent Celek lauded Foles' reads and his command of the huddle.
Fletcher Cox rebruised his tailbone in the first half but returned to the game...Kurt Coleman was down for a long time after tackling Jason Witten midway through the fourth quarter. He suffered what was announced as a sternum bruise. Andy Reid said X-rays were negative but Coleman will get an MRI Monday.
On Twitter: @LesBowen