"We've got to understand this is a tough-ass league, and you're playing some really good teams," Kelly said. "I tell people all the time [that] 90 percent of people don't care about your problems, and 10 percent are glad you have them."
And the Eagles' problems on Sunday were plentiful. They could not stop Broncos quarterback Peyton Manning with their defense. They could not keep pace with Manning on offense, and they allowed two touchdowns on special teams. Although the Eagles entered the game heavy underdogs, they appeared even less competitive than anticipated.
Manning left Sunday's game with more than 10 minutes remaining. His day was complete, and it was even better than the Eagles had feared. The Broncos quarterback finished 28 of 34 for 327 yards and four touchdowns. Demaryius Thomas and Wes Welker each had two scores.
Eagles quarterback Michael Vick completed 14 of 27 passes for 248 yards and rushed for 41 yards. He did not turn the ball over and was sacked three times. LeSean McCoy rushed for 73 yards on 16 carries, but DeSean Jackson caught only two passes for 34 yards.
Manning took an eight-point halftime lead and added three third-quarter touchdowns without the Eagles scoring a point. Kelly said the turning point was the Eagles' failing to respond after Manning's first second-half touchdown. The Broncos possessed the ball for 11 minutes, 53 seconds of the third quarter and had 16 first downs without ever getting to third down.
"We knew what we were coming into, but we wanted to play the best, and we wanted to beat the best," safety Nate Allen said. "But they just beat us today. That's the bottom line. They out-executed us. In the second half they made some adjustments, and they were just executing."
Those scores were all the Broncos needed. The Eagles defense had no answer for Manning, and Kelly's offense could not keep pace.
The Eagles settled for two first-half field goals when they knew they needed touchdowns. All week, the offensive players acknowledged they needed to score to offset Manning. A Brent Celek drop on third and 4 in the first quarter cost the Eagles a first down, and a Lane Johnson holding penalty in the red zone on the next drive forced the Eagles into a long-yardage situation. Both drives ended with three points, not seven.
"When you play a Peyton Manning team, you can't stop yourself," Kelly said. "A couple critical drops and a couple critical penalties really handcuffed us offensively."
The Eagles' best chance to stay in contention came in the first half before Manning completely had his way with the Eagles defense. But those field goals kept the Eagles trailing, and they could never take momentum away from Manning.
After the Eagles' first field goal, Broncos returner Trindon Holliday sprinted past the Eagles kickoff coverage unit for a 105-yard touchdown return, one of two Denver special teams scores. The Broncos later returned a blocked punt for a score.
The Eagles cut Denver's lead to 14-13 with a Chris Polk touchdown in the second quarter. But Manning drove the Broncos 80 yards and was 5 for 5 passing to extend the lead back to eight points.
Kelly made a critical decision on a fourth down during the Eagles' next drive when he decided to punt instead of going for it on a fourth and 6 on the 37-yard line. He said he didn't want to give Manning a short field if they came up short and that a field goal would have been out of kicker Alex Henery's range.
The Broncos didn't score again in the half, but the Eagles didn't score again until late in the fourth quarter. That score, a 6-yard pass from Nick Foles to Jeff Maehl in garbage time, cut Denver's lead to 32 points.
The Eagles' next two opponents - the New York Giants and Tampa Bay Buccaneers - are both winless this season. Those games could determine whether the Eagles can be competitive in Kelly's first season.
After three consecutive losses - and Sunday's humiliating defeat - the Eagles have plenty of problems to address. Kelly said the key for the Eagles is quickly moving past Sunday's loss.
"I don't think this was a 'Holy smokes, the season's over,' " Kelly said. "Every week is a season."