The impetus for Denver's metamorphosis was "The March."

The Jaguars jump-started their 23-14 thumping of the Broncos at Invesco Field last September with the longest drive in franchise history, an 18-play, 80-yard torture test that lasted nearly 12 minutes.

When it was over, on David Garrard's 3-yard TD toss to Reggie Williams - against 12 defenders, no less - the Broncos knew something else had to give.

The tone-setting drive had far-reaching effects, leading to a shake-up of Broncos defensive bosses, a shift in philosophy and an overhaul of personnel.

Out went Jim Bates, his eight-man fronts and his lean linemen.

In came Bob Slowik, his beefier tackles and simpler play book.

The switch heralded the introduction of the Broncos' hybrid defense that shifts from the traditional four down linemen to four linebackers from series to series, confounding quarterbacks and opposing coordinators alike.

"They've made some changes. They are not the group that was a smaller bunch up front last year," Jaguars running back Fred Taylor said. "They put together a very good defense, a lot better than they were last year. They're young, they're energetic."

Although the Broncos' D ranks 29th in the NFL and their offense ranks second, Denver's defenders have made key stops at crucial moments during the team's surprising 4-1 start, and last week they forced seven punts in a 16-13 win over Tampa Bay in their best showing yet.

"We've got too much talent not to be good," cornerback Champ Bailey declared.

The Jaguars (2-3) bring the same offensive powerhouse into Denver for the rematch, led by Garrard, Taylor, fellow running back Maurice Jones-Drew and leading receiver Matt Jones.

Not that the Broncos need any reminders of their big loss to Jacksonville.

"They manhandled us last year," Broncos coach Mike Shanahan said.

"They beat us up really good," agreed receiver Brandon Stokley.

"I do remember them running the ball down our throats," offered defensive end Jarvis Moss.

"It was the turning point in the season," suggested defensive back Karl Paymah. "It was a big loss for us."

The Broncos won't soon forget the Jaguars' maintaining possession for 38:42 and out-rushing them 186 yards to 47, or Garrard completing 14 of 20 passes and rumbling for 52 yards himself.

But "The March" is what hurt the most.

"We've been doing that since I've been here, running the football and trying to keep the other team's offense off the field," Shanahan said. "And it's really discouraging when it happens to you."

Last year, the Broncos were feeling good about themselves after pulling out two last-minute wins. They never recovered from their loss to Jacksonville, which exposed so many weaknesses and began a 5-9 slide that resulted in Denver's first losing season since 1999.

The Jaguars, meanwhile, rode their momentum right into the playoffs.

"We're in the same position we were in last year," Paymah said. "We have to capitalize this time."

The Broncos feel they have the defense to stop the Jaguars this time, even though they've been burned by big runs time and again. They note Larry Johnson's 198-yard effort came when tackle Dewayne Robertson was sidelined with a knee injury.

The Broncos expect this week's game to be a similar slogfest to last week's in the rain against the Bucs.

"We are putting more emphasis on stopping the run," linebacker Nate Webster said. "We showed it last week."

That's when the Broncos activated seven defensive linemen and seven linebackers, and rotated Robertson, Kenny Peterson and Nic Clemons in the middle to stuff Tampa Bay's physical run game.

"That wears an offensive line down because offensive lines don't rotate," Broncos linebacker Boss Bailey said.

Shanahan said the Jagurars present an even tougher test than Tampa Bay.

"I know they are going to come in here and run the football just like they did last year. It will be a great challenge to our defense to slow them down," Shanahan said.

The Broncos might very well need an encore from their defense because they're missing two key starters in tailback Selvin Young and tight end Tony Scheffler, who are out with strained groins.

Also, rookie receiver Eddie Royal, who is third in the AFC with 30 catches, has a sprained left ankle that could keep him out, and flanker Brandon Marshall was sick this week.

The Jaguars have had their share of injuries and bad breaks, too. All of their games have come down to the fourth quarter and none have been decided by more than a touchdown.

"Only dogfights to the very last second," Taylor said. "So, we're prepared to play 60 minutes all-out."

Garrard said he feels the heat of Denver's high-octane offense, averaging 30 points a game.

"They can put up big numbers, so we have to try to match that," he said.

But rather than a shootout, Garrard wouldn't mind playing keep-away again.

"We are going to try to stay on the field a little longer to eat up some of the clock like we did last time," he said.

The Broncos have spent the last 12 months trying to prevent just that.