OAKLAND - Remember that confident talk all last week from the Eagles about not taking the Oakland Raiders lightly, regardless of their record?

Yeah, well . . .

The Birds left the Bay Area last night still insisting they'd come in prepared and girded and focused and all that good stuff, they'd just somehow neglected to then reflect that in their play. The Black Hole ate their homework.

Worst loss of the Andy Reid Era? Well, no. It wasn't the NFC Championship Game, it wasn't even a critical regular-season game. Silliest, most inexplicable loss? Much more likely.

"The most disappointing ever," offered cornerback Asante Samuel, who repeatedly tackled air, and took a terrible penalty that helped set the tone for the afternoon.

"Whether it was the Eagles or whoever, it was great to, you know, win," said Oakland coach Tom Cable, heretofore famous for allegedly slamming an assistant coach into a piece of furniture. Cable took a 15-yard penalty yesterday for running onto the field and throwing his headset when an interception return for a touchdown was ruled interference.

The now-2-4 Raiders knocked Eagles left tackle Jason Peters out of the game early (left knee, MRI today), then took control with a lightning-strike touchdown to tight end Zach Miller that turned out to be the only TD of the afternoon, and also the turning point. Once they'd convinced themselves they could actually play with the 15-point favorites from the NFC East, the Raiders controlled both lines of scrimmage in a 13-9 victory that was as big an upset as you will see in the NFL this season. In fact, unofficially, you have to go back to 2001 and Arizona, when the Birds lost despite being favored by 16, to find a bigger Eagles point-spread upset.

"I can speak for myself, and I should speak for everybody; I'm embarrassed by the way we came out here and played; we're a better team [than that]," said Eagles quarterback Donovan McNabb, who finished 22-for-46 for 269 yards and a 66.3 passer rating, while taking six sacks from what had been the league's 31st-ranked defense.

In his second game back from that opening-day rib injury, McNabb looked like the creaky, hesitant 2007 Donovan, the QB who was working his way back from ACL surgery. But even that McNabb didn't have to try to come from behind in a hostile stadium with King Dunlap and Winston Justice as his tackles. (Time to fire up the Jon Runyan watch again, by the way.)

"It's hard to get the ball out when you've got guys on you," McNabb said, when asked about the sluggish pace of the Birds' passing game, in the teeth of what seemed to be all-out blitzing.

"They did some things we weren't really expecting, that they didn't really show the first couple of games. We were caught by surprise," said Justice, who is starting to look more like the inexperienced tackle he really is, the more film foes have. "Beforehand, they weren't really a team that blitzed as much as they did us this game. It was a shock. God willing, we have another chance next week."

Indeed, unless a merciful deity intercedes, the 3-2 Eagles will visit the 2-4 Redskins next Monday; Washington managed to lose to the Chiefs yesterday.

There were plenty of other offensive issues; Reid, as is his custom, abandoned a running game that was working (better than the passing game anyway) because he was trailing. Many NFL coaches, the Daily News has learned, would not be inclined to do so in a game in which they never trailed by more than seven points.

"Looking at it, we had some success running the ball. If we had run it more, we might have had more success," said Brian Westbrook, the most productive Eagle, with six runs for 50 yards (8.3 yards per carry) and nine catches for 91 yards. Somehow, Reid didn't seem to grasp that on this day, Westbrook and rookie LeSean McCoy were not interchangeable. McCoy, whose five carries netted 13 yards (and a fumble the Birds recovered), who didn't catch a pass, alternated series with the veteran all afternoon. As a result, Westbrook was not on the field for some crucial second-half third downs. The Birds converted two of 16 third downs, by the way.

"That's the way coach is doing it now," Westbrook offered. "You know, I just go out there and play, any chance I get. Coach feels comfortable with LeSean in there. He's a very good player; he's made some very big plays thus far this season."

Asked how his knee and ankle felt, Westbrook said: "I felt pretty good. When I had an opportunity, I felt pretty good."

The uh-ohing started early, when Peters went down with a left knee injury on the Birds' third drive. Actually, it started before that, when Brent Celek whiffed on a block on the Eagles' very first third down and Trevor Scott sacked McNabb. But the Peters injury intensified some early confusion on the o-line, and the Eagles didn't adjust well.

When Raiders quarterback JaMarcus Russell, who netted 64 passing yards the week before in the blowout loss to the Giants, found tight end Miller over the middle, isolated against Jeremiah Trotter, the Raiders were off to the races. Miller caught the pass, outran Trotter's tackle attempt, picked up blocking, including a clutch walling off of Ellis Hobbs by Louis Murphy, and rambled 86 yards for a touchdown that turned the game upside-down, though it gave the home team just a 7-3 lead, with 2:05 left in the first quarter.

"We had a blitz on. They had a great play action," Trotter said. "I bit on the run. When I got back on the tight end, he came across the field."

A little perspective here: The Raiders came in netting an average of 108 yards passing per game. They got 86 on one play. Russell, who spent the week being ridiculed nationwide for his weight and his overall regression since being drafted first overall in 2007, went on to complete 10 of his first 13 passes, for 147 yards. Granted, two of the three incompletions were picks, but still - the Eagles gave Russell hope, and he grabbed it.

"A team like that, man, that's not usually used to winning, you give 'em a little hope and let 'em play with you, they gain more and more confidence," said McCoy.

The Eagles could not capitalize on mistakes, or get out of their own way, really. The rock-steady Celek dropped passes. Neither Reid nor McNabb seemed able to improvise on the fly; whether by play design or QB indecision, the ball took way too long to get out of the quarterback's hand, again and again and again. The officiating crew didn't help. One Richard Seymour sack, he was obviously offside. Another, as the Eagles strained to score at the end of the first half, should have been a clock-stopping false start on Nick Cole, but wasn't.

Meanwhile, Samuel let himself be baited into a stupid retaliatory penalty, right out of the Claude Lemieux handbook, helping set up a Raiders field goal. David Akers missed 47- and 44-yard field goals, enough wasted points to win the game. Every third-and-long in the second half seemed to be a 50-yard incompletion, instead of something a little easier to manage, on a tough day. Six passes were thrown to Jeremy Maclin, who had one catch, for 6 yards.

Michael Vick trotted onto the field twice; once, as a wideout, he lost 4 yards on an end-around, the other time, the Birds had to burn their final timeout, with 27 seconds left in the first half, to figure out what they were doing.

Injured Eagles were being helped off the field left and right - defensive end Victor Abiamiri (knee), middle linebacker Omar Gaither (foot), defensive tackle Brodrick Bunkley (ribs, though he returned), safety Quintin Mikell, who left briefly after a big collision, DeSean Jackson, who missed a series after being blatantly tackled out of bounds on a punt return (no penalty).

The only saving grace might have been that McNabb, who took about a dozen hard shots, was never among those needing assistance. Only head athletic trainer Rick Burkholder spent more time kneeling on the Oakland-Alameda County Coliseum turf than the quarterback.

"It goes back to making plays when the plays are there to be made," McNabb said. "I thought we didn't do that today. And again, it starts with me . . . That won't happen again. I will make sure that the rest of the guys around me understand the sense of urgency. We will make plays and do what we have to do to win ballgames."

For more Eagles coverage and opinion, read the Daily News' Eagles blog, Eagletarian, at www.eagletarian.com.