Almost every week, no matter how many important plays there are in a game, no matter how many big hits, no matter how many great runs or timely passes, at the end it always seems that DeSean Jackson was in the middle of everything that mattered.

That isn't the case. A football game is a complicated puzzle to solve, with nearly 150 plays and delicate momentum swings that can't always be charted. But, for the Eagles this season, as they have struggled to survive with a mix-and-match defense and without one of the most productive offensive players in recent memory, it has been Jackson around which the game often revolves.

He did it again today in a 27-13 win over San Francisco that should have been a lot easier. Jackson caught a touchdown pass on the first drive of the game, his 11th touchdown of the season, and he totaled at least 140 yards receiving for the second straight week.

The biggest play of the game, however, came early in the fourth quarter, as the Eagles were deep in their own territory, trying to regain momentum after seeing a big first-half lead shrink to just seven points.

Facing a third and 2 from the Eagles' 19-yard line, offensive coordinator Marty Mornhinweg called for a deep pass to Jackson, a simple out-and-up route that was as aggressive as it was risky.

If the play failed, the Eagles would punt, the 49ers would have good field position and it was possible that even Alex Smith, a quarterback who didn't distinguish himself today, could grab that opportunity and turn this into a very dangerous game.

It wasn't as if the Eagles didn't have much to risk. today's win clinched a playoff berth and, even if they were to lose Sunday against Denver, puts some of their postseason fate in their own hands. If they win at Dallas in the final game of the regular season, they win the NFC East and are assured of at least one home game in the playoffs.

The 49ers, fighting to stay statistically alive for the postseason and fighting to get back to a .500 record, just had to keep the Eagles hemmed in. If they allowed a first down, well, the Eagles would need a few more and a long drive to get their insurance score.

In fact, the only thing that could really hurt them was a long play to the only deep threat on the field. But, seriously, with all that Jackson has accomplished this season, with how he has established himself as one of the most dangerous players in the league, the 49ers couldn't possibly let him get behind them, could they?

"It's a confidence play, because Marty believed that call would be a success," quarterback Donovan McNabb said. "Confidence that DeSean has the effort and ability to create separation and make the play."

And that's exactly what happened.

The cornerback bit on the out fake, tried to grab Jackson as he turned quickly and headed downfield, but all he got was a look at the back of the receiver's jersey. McNabb threw a strike and 59 yards later, the Eagles were set up at the San Francisco 22-yard line, on the way to a LeSean McCoy touchdown that effectively sealed the win.

"It doesn't matter if it's third and an inch," Jackson said. "They have that kind of confidence in us."

The numbers are piling up like the drifts of snow outside the stadium today. Jackson went over 1,000 yards receiving for the season, just the third Eagles receiver to reach that plateau during Andy Reid's tenure. (Terrell Owens in 2004 and Kevin Curtis in 2007 were the others.)

This season, the offense has gained 30 or more yards on a single play 31 times. Jackson has been the receiver or the runner on 14 of those. Ten of his 11 touchdowns have come on big plays, including a pair of long punt returns.

In fact, his only "routine" touchdown was today's 19-yard pass on a scramble play. McNabb was running around, trying to buy some time and Jackson followed along, finally breaking open on a long right-to-left slant.

"It was a curl route and he scrambled and I scrambled with him. It's not how the play was designed but we stuck with it," Jackson said.

Even though Jackson was exciting last season, there was no way to know he would be able to replace the production of a Brian Westbrook, who had 14 touchdowns in 2008. Westbrook scored two touchdowns this season, but has been inactive in seven of the last eight games since suffering a first concussion on Oct. 26.

"When you lose him, you lose an important part of the offense," Reid said. "These kids have given us energy. They're fun to watch. They make mistakes here and there, but they do it at 100 miles per hour."

Jackson does everything at that speed, and the mistakes have been few.

"He plays like we all did as kids in the backyard. He's having fun," Reid said. "And he's doing it in the NFL. That's amazing."

And it's also amazing that a team that has endured as much adversity as the Eagles could lock up a playoff spot with two games to play and has an excellent chance to win the division. Last year, it took five miracles just to get them in the postseason.

"We're grateful for the position we're in, but we don't get caught up in all that," Reid said.

Jackson does, though. He plays with his heart on his jersey sleeve and, usually, with the opposition five yards behind and gasping. He isn't the only reason they've gotten to this point, but he always seems to be the one everyone is talking about at the end of the day.

Contact columnist Bob Ford at 215-854-5842 or bford@phillynews.com.