That left the 49ers groping for answers after a 38-17 whipping that easily was their worse loss since they became contenders again following the 2000 season.
"I'm embarrassed at the way we played as a team," said star receiver Terrell Owens, breaking five weeks of silence to lament the Niners' shoddy performance. "Maybe we were too hyped to play. I don't know what happened."
That was a feeling going around Monday like a virus that infects everyone in its path. And it started spreading early in the first quarter, touching the Niners in every area and phase of their game.
By the end, it became an epidemic of bad snaps, dropped passes, missed assignments and blown coverages by the Niners. And it all tumbled down hard afterward on coach Steve Mariucci, who said, "I take full responsibility," for the loss.
"Today they were better on offense, on defense and in the kicking game than we were," Mariucci said. "It's as simple as that."
And also, as complicated as that to understand.
The Niners appeared as ready for this game as any they have played this season. Coming off a tough loss at San Diego the previous week, they had an extra day to prepare for an opponent that had lost its MVP-candidate quarterback the week before and had little success when it came to San Francisco amid similar circumstances last season.
But this time, the Eagles were all over the Niners.
Before he dislocated his left elbow in a scary incident that halted play for several minutes in the third quarter, the Niners made Detmer look like a Pro Bowl star instead of a backup.
Detmer completed 18 of 26 passes for 227 yards, connecting with Todd Pinkston on a 25-yard touchdown throw and with Antonio Freeman on an 11-yard scoring play. He also beat the Niners several other times on big passing plays down the field and finished with a quarterback rating of 121.8.
After he was injured, Detmer was replaced by third-stringer A.J. Feeley – the only other quarterback the Eagles had dressed Monday. Feeley completed all three of his passes, had a quarterback rating of 129.9 and also threw the touchdown pass to tight end Chad Lewis that gave the Eagles an insurmountable 35-10 lead late in the third quarter.
That's how bad it was for the 49ers.
So was this: Their kick coverage units were embarrassed even worse than their secondary coverage packages.
Less than four minutes after the Eagles assembled a 12-play, 90-yard touchdown drive to break a scoreless tie that had lasted into the second quarter, Philadelphia hit the Niners with a bolt of lightning from which San Francisco never would recover.
Brian Mitchell took a punt at his own 24-yard line, burst through San Francisco's coverage unit and raced down the right sideline for a 76-yard return that put the Eagles up 14-0 and made the Niners suddenly realize they were in for a long evening.
It got longer.
While the Eagles were having their way with San Francisco's defense and special teams, the Niners weren't faring much better against Philadelphia's highly-regarded defense.
San Francisco was forced to punt on each of its first four possessions, and then turned over the ball on downs on its final three possessions while attempting to play catch-up from way behind in the fourth quarter.
Quarterback Jeff Garcia was harassed as he seldom has been this season, and he also was a victim of penalties, bad snaps and dropped passes. Two of the drops were by Owens, who otherwise had a prime-time performance with game-high totals of 13 receptions for 166 yards and both San Francisco touchdowns.
But he was one of the few to produce in such fashion for the 49ers.
"We didn't play well at all," Garcia said. "From the opening snap, we just never got it done. We didn't play well in any sort of way. It was just bad altogether. I was bad."
Actually, Garcia was better than that, completing 29 of 51 passes for 284 yards – including touchdown throws of 3 and 18 yards to Owens – before he was pulled late in the fourth quarter because the game had gotten out of hand.
And who ever would have expected that to happen on this night? Not the Nine