The Washington Redskins' defense occasionally held players-only meetings last week in preparation for Sunday's season opener against the Tampa Bay Buccaneers. As the 24 players watched film of Tampa Bay's offense on a big screen, middle linebacker Antonio Pierce acted like the missing coach, with assistance from injured linebacker Mike Barrow.

Pierce dissected plays while generating images from a computer. When the Bucs' offense showed certain formations, Pierce quizzed teammates on how to counter them. Pierce reminded the outside linebackers and defensive backs that it was important to constantly communicate between plays.

"It was impressive," safety Matt Bowen recalled yesterday at Redskins Park. "He's one of the smartest players I've ever been around and one of the hardest workers."

Pierce was impressive during Sunday's 16-10 victory at FedEx Field as Tampa Bay was held to 169 total yards, giving Washington's defense the NFL's top ranking after Week 1. With the game tied at 10 early in the fourth quarter, Pierce intercepted a Brad Johnson pass and sprinted 16 yards, helping set up John Hall's 30-yard field goal to give Washington a 13-10 lead.

But just as significant was the leadership and football intelligence Pierce exhibited quarterbacking assistant head coach-defense Gregg Williams's complicated formations. Pierce barked out tips to teammates and exuded confidence unusual for a player making his 11th NFL start. Pierce aligned his teammates and deciphered the Bucs' formations to call the appropriate defenses. Perhaps the most remarkable aspect of Pierce's display was that he was calling plays quicker than some assistants.

"Super smart," Coach Joe Gibbs said Monday.

Pierce, 25, has used his football smarts to become a key player in Washington's defense this season after being an obscure reserve linebacker since joining the NFL in 2001. An undrafted free agent from Arizona, the 6-foot-1, 240-pounder mostly had contributed on special teams.

Pierce said it has been hard learning middle linebacker because of the added complexities of the position. But by training camp, Pierce progressed enough to be considered Washington's fourth-best linebacker because of his athletic ability and versatility. The other starters are weak-side linebacker LaVar Arrington and strong-side linebacker Marcus Washington.

Barrow, 34, was expected to start after playing every game last season while amassing a career-high 177 tackles with the New York Giants. But Pierce's play makes it difficult to have him come off the bench, even when Barrow recovers from knee tendinitis.

Pierce "is a guy that we've got to have in the game," Gibbs said. "Now where is [that position] going to be when [Barrow] gets back? I think we'll just have to make a good decision on defense. But he's somebody who has to be playing all the time."

Linebackers coach Dale Lindsey said he looked at the Barrow-Pierce situation favorably, and added, "We'll cross that bridge when it comes."

Lindsey noted that it's difficult to discern starters in Williams's system because he freely rotates players in and out of the game to conserve their energy. On Sunday, 18 players contributed.

Despite blitzing an estimated 70 percent of the time, the Redskins' defense worked well together -- players were almost always in the right spot. "There's definitely a method to the madness," Washington said yesterday. "Guys aren't running around blindly. You need 11 guys in sync."

The middle linebacker generally holds the most responsibility for properly aligning players. It's a particularly difficult job in Williams's system because of the complexity of his defense. Williams uses up to 16 formations and disguises his schemes by moving players in various sets, making it harder for offenses to detect blitzers. Pierce must know the placements of his teammates for various offensive formations. "He must know everything," Bowen said.

On Sunday, when defensive linemen weren't able to hear Pierce's instructions, the linebacker quickly would run up to them and convey the message, tapping them for encouragement. If Bucs tight end Ken Dilger switched from the right side to the left, Pierce instantly yelled the proper defensive adjustment.

"Not everybody can do that. I'm glad I'm not a Mike [middle] linebacker," Washington said.

Teammates believe that Pierce possesses an innate grasp of football, yet bolsters his knowledge by being a student of the game. During team meetings with coaches, Pierce is more of a listener -- scribbling extensive notes -- than in players-only gatherings.

Washington's new coaches started to see Pierce's cerebral side during minicamps, and he had a strong preseason. However, the coaches didn't know how Pierce would react during a regular season game. "Out here you can make a mistake," Lindsey said, "and it doesn't matter. There's a huge difference with a real game."

Bowen saw signs of Pierce's football acumen last season, when he demonstrated that he understood all aspects of every special teams unit.

Against Tampa Bay, Pierce showed his competitive side, getting upset when he was removed from some special teams units. "He went up to Danny," Gibbs said, referring to special teams coach Danny Smith, "and said, 'I can do everything.' "

Redskins linebacker Antonio Pierce returned an interception 16 yards to set up a key field goal in the 4th quarter of a 16-10 victory over the Buccaneers. Redskins assistant head coach-defense Gregg Williams, left, and Antonio Pierce stay on the same page during Washington's season-opening win.