The final game of the Giants’ season was much like the season itself: It got off to a promising start but quickly turned ugly. With yesterday ‘s 23–20 loss to the Philadelphia Eagles, Tiki Barber’s Giants career definitely came to an end, Tom Coughlin’s probably did, and Eli Manning failed to silence the growing criticism that he simply doesn’t have the makeup of a first-rate quarterback.

In his final game, Barber turned in a great performance, with 137 rushing yards. Barber exits as one of the greatest Giants in franchise history, the owner of the team records for rushing yards in a career, a season, and a game, as well as the record for career catches. The Giants have retired the numbers of 11 players, and Barber will no doubt be the 12th.

Barber is retiring at the top of his game. Not even Jim Brown or Barry Sanders, the Hall of Fame running backs who set the standard for leaving on top, gained as many yards as Barber in their final seasons. Although the Giants would love to change his mind, Barber has a career in television ahead of him and seems firm in his decision to retire.

Giants fans will always have fond memories of Barber, but if yesterday was Coughlin’s final game as the Giants’ coach, his tenure with Big Blue will be judged a failure. As much as Coughlin’s dictatorial style seemed to toughen the Giants last year, it wore them down this year. The loss drops Coughlin’s record in New York to 25–25, and it’s hard to argue that the franchise is any better off now than it was when he replaced Jim Fassel three years ago.

For a coach who preaches discipline as much as Coughlin does, mistakes plagued his team all season, and those mistakes continued yesterday. The Giants were called for nine penalties in Philadelphia, including five false starts on offensive linemen. The Giants wasted two timeouts in the fourth quarter: one when Jared Lorenzen, Manning ‘s 285-pound backup, came in for a quarterback sneak on third-and-1 but didn’t see the formation he expected, and one when Manning didn’t get the play in time on a third-and-12. Those wasted timeouts — which cost the Giants dearly when the Eagles ran off all the remaining time before kicking the winning field goal — were two of the many times the Giants looked disorganized, and the coach has to bear primary responsibility for that.

“The great lesson is, obviously, not to waste your timeouts,” Coughlin said at his postgame press conference.

If Coughlin is fired, the next coach’s top priority will be developing Manning, which means the Giants will look for a coach with a proven track record of molding young quarterbacks. Manning isn’t a bad quarterback, but he isn’t as good as the Giants thought he would be when they gave up a king’s ransom to acquire him in a draft-day trade in 2004.

On the Giants’ first drive yesterday, Manning went 3-for-3 for 55 yards, and the drive concluded with a touchdown pass to Plaxico Burress. On the Giants’ last drive, Manning went 6-for-7 for 66 yards, and the drive concluded with another touchdown pass to Burress. But for the rest of the game, Manning made mistakes, missed open receivers, and looked confused. He threw an interception when he forced a pass to a heavily covered Burress — a mistake typical of rookies that Manning hasn’t stopped making in his three-year career.

Although grooming Manning and replacing Barber will be the keys to the off-season, the defense has issues as well. Defensive end Michael Strahan is 35 years old and coming off a serious foot injury. Strahan has been a great player — arguably the second-best defensive player in the history of the franchise — but it’s hard to imagine him continuing to be a great for much longer. The Giants’ young defensive ends, Osi Umenyiora and Mathias Kiwanuka, need to become the leaders of the defense.

Cornerback seems like the most likely position for the Giants to address in April’s NFL draft. Big Blue started veterans Sam Madison and R.W. McQuarters yesterday, and both players are past their primes. The Giants desperately need an injection of young talent into the secondary.

And perhaps the most overlooked question for the Giants’ offseason is who will acquire that talent. General manager Ernie Accorsi is retiring, and it’s unclear who will take his place. But whoever it is, he’ll have a mandate for change: The loss to the Eagles was the final chapter of a season in which the Giants took a step backward.