Carson Wentz threw a pair of touchdowns passes as Philadelphia scored on its first three possessions of the second half and surged to a 37-9 victory at AT&T Stadium.
Not even an injury to kicker Jake Elliott could slow down the Eagles after halftime.
Elliott was being evaluated for a head injury late in the first quarter and didn't return to the game. He made an extra point and missed a 34-yard field goal before his exit.
With their kicking game limited, the Eagles went for two after each of their second-half touchdowns. Wentz made good on two of them with passes to Alshon Jeffery and tight end Trey Burton, and running back Corey Clement ran for another one.
Wentz converted a fourth-and-5 from the Dallas 17 when he connected with Jeffery for a touchdown that put Philadelphia ahead 29-9 with 12:10 left in the fourth quarter.
The Eagles (9-1) held Dallas to 225 yards of offense.
Philadelphia's defense also came up with the exclamation point on the win when defensive end Derek Barnett sacked Dallas quarterback Dak Prescott and forced a fumble. Eagles linebacker Nigel Bradham scooped the ball and returned it 37 yards for a touchdown.
Prescott completed just 18 of 31 passes for 145 yards, three interceptions and the costly fumble. Philadelphia sacked Prescott four times, keeping Dallas (5-5) from establishing any momentum on offense.
Wentz's stellar second half helped him finish with 168 passing yards on 14-of-27 passing.
The Eagles drove 75 yards on their first possession of the game and took a 7-3 lead when running back Kenjon Barner ran four yards for a touchdown with 9:16 left in the first quarter.
But the Dallas defense, which has struggled with linebacker Sean Lee out of the lineup, found a way to slow down the potent Philadelphia offense for most of the first half.
Even when the Eagles set up at the Cowboys' 15-yard line following safety Rodney McLeod's interception of a Prescott pass, the Cowboys turned away Philadelphia with no points.
After a pair of Wentz incompletions, Elliott missed a 34-yard field goal wide right.
The Cowboys defense forced Philadelphia to go 0-for-6 on third downs in the first half.
Dallas kicker Mike Nugent kicked field goals of 48 and 27 yards to cap the Cowboys' first two drives, keeping Philadelphia's lead to 7-6 for most of the first half.
Nugent's third field goal of the first half, a 47-yarder on Dallas' final possession of the second quarter, boosted the Cowboys to a 9-7 lead at the break.
NOTES: The Cowboys and Eagles, who were playing for the first time this season, split their series in each of the last four years. Last season, Dallas had already clinched the NFC East when the Cowboys traveled to Philadelphia for the final game of the regular season, which the Eagles won, 27-13. Dallas won the first meeting a year ago, 29-23, in overtime in Arlington. ... The Eagles entered the game averaging 31.4 points, second in the NFL behind the Rams and they are now at 32.0. Philadelphia was on pace to set a franchise record for average points. The Eagles' 1948 NFL championship team averaged 31.3. ... The Eagles gave up just 598 rushing yards through their first nine games, the best per-game average in the NFL. ... Cowboys RB Darren McFadden was a healthy scratch for Sunday's game, meaning Dallas had just two active running backs.