Steve Smith ended one of the longest games in NFL playoff history with a 69-yard touchdown. AP

ST. LOUIS -- In a game that had almost a comical amount of twists and turns and reversals of fortune, it's altogether fitting that the play that decided things is called X-Clown.

You'll forgive the St. Louis Rams if they don't find much humor in the name. But it sure put a smile on the face of every Carolina Panther.

When Panthers receiver Steve Smith scooted 69 yards on the first play of the second overtime period, ending the fifth longest playoff game in NFL history, Carolina head coach John Fox was more relieved than anything else. This wasn't a game to be celebrated as much as survived.

"I think I was too drained by then to get too high,'' said Fox, after the amazing sequence of late-game events left his Panthers a 29-23 winner of Saturday's NFC Divisional round game at the Edward Jones Dome. "All of us were pretty drained. There was a lot of emotion. I've never seen a game quite like that. There were as big a peaks and as big a valleys as you could have. It was as good a football game as I've ever been involved in.''

So many things jump out at you after a game like this, in which there were six lead changes and the wildly improbable occurrence of an apparent game-winning overtime Carolina field goal being wiped off the scoreboard by a delay-of-game penalty. But those 75-plus minutes of gripping playoff football produced several meaningful revelations.

First things first. These Cardiac Cats are for real, NFL fans. Carolina (13-5) was a big underdog, and lost its leading rusher, Stephen Davis, early in the second quarter after he injured a quad muscle. No matter. The Panthers are now 4-1 in overtime this season and 10-2 in games decided by six points or fewer. Fox's guys know how to stay close and win in the end, and their blueprint worked again against St. Louis (12-5), which had won 14 consecutive home games dating to September 2002.

Entering the game, NFC road teams were a mind-boggling 2-24 in the Divisional round since the 12-team playoff format debuted in 1990. But No. 3-seed Carolina made it 3-24 by knocking off the second-seeded Rams. The buzz in this year's postseason has been that Green Bay is the team of destiny, with more good karma going for it than any other remaining playoff qualifier. But we might have to rethink that supposition, because nobody can match the Panthers for finding ways to prosper on the narrowest of margins.

"We've had more close games than I'd like to remember, today included,'' said Fox, whose team could host the NFC title game next week if Green Bay upsets Philadelphia on Sunday. "But they believed in it and they didn't lay their sword down, and there were a lot of reasons to lay down your sword. But nobody did.

"We have a formula and we go about it and we have a lot of low-scoring games and a lot of close games because of it. We were saying when it went into overtime, 'Hey, we've been here as much as anybody.' And they believed that.''

Nobody personifies the Panthers' moxie more so than quarterback Jake Delhomme, whose only touchdown pass of the game advanced Carolina into the NFC Championship Game for the second time in franchise history and first time in seven years.

"We just believe we can get it done some kind of way," said Delhomme, who oversaw a Carolina offense that produced a whopping 485 yards, 216 of those on the ground.  "The biggest thing is we stayed calm. It's, 'Hey, we've been here before. Let's go get it done. Let's get it done.' ''

Belief wasn't contagious on both sides of the field Saturday. For the losing Rams, there was much to be desired in that department. It was hard to watch how this game went and believe that in his heart of hearts St. Louis head coach Mike Martz has confidence that Marc Bulger is his quarterback of the future. Trailing 23-12 with six-plus minutes to go, the Rams mounted a furious 11-point rally to tie the game and force overtime.

But what will be remembered is that Martz chose to play it safe at the end of regulation, rather than put the game in Bulger's hands. Facing a second-and-4 at the Panthers' 19 with 42 seconds remaining, the Rams chose to run Marshall Faulk once and then bleed the clock down to three seconds, positioning for a 33-yard Jeff Wilkins field goal.

The strategy was a window into Martz's soul in terms of his quarterback question. With Bulger having thrown two horrible interceptions in the fourth quarter, Martz wasn't willing to let his quarterback take even one shot at the end zone, which could have finished off a Panthers team that was on the ropes and reeling. Instead, he rolled the dice on his team in overtime and lost. Can you say Kurt Warner in 2004? I think you'd be wise to lean that way if you're trying to handicap Martz's mind.

"I was really concerned about throwing it into the end zone and having a ball tipped or bumped,'' Martz said, when grilled on his dubious decision-making. "I just wanted to get this thing into overtime. I thought if we got this thing into overtime we could win the game. That's why I did that. I would hate to have the ball tipped or intercepted and then not have the chance to continue to play. I felt that was the right thing to do at that point in the game.''

Martz wound up losing more than the game; he might have lost a few believers in his own locker room. His always aggressive nature was often tamed this season, as he took pains to protect Bulger and keep him in situations where success was likely. But it's hard to escape the following facts: Martz didn't trust a guy who was 13-0 as a starter at home before Saturday and 18-3 in games he both started and finished for the Rams.

"I can't make the calls,'' Rams receiver Torry Holt said of Martz's conservative approach to end regulation. "I have to go by what's called. Coach felt that was the approach he wanted to take in order to give ourselves a chance to win. ... That was his decision and how he felt at the time.''

Bulger finished 27 of 46 for 332 yards passing, but he had no touchdowns and it was his third and final interception -- to Panthers cornerback Ricky Manning Jr. at the Carolina 35 late in the first overtime -- that set up Smith's game-winning catch three plays later.

If the fans were making the call at quarterback for 2004, Bulger wouldn't stand a chance in St. Louis. He was booed lustily at times against Carolina.

"I'm used to that by now,'' Bulger said. "They have been booing all year. That doesn't bother me."

Juxtapose Martz's faltering faith in Bulger with Fox's rock-solid belief in Delhomme, the first-time starter who was signed away from New Orleans in free agency last offseason.

"The bigger the game, the better he gets,'' Fox said of his quarterback, who finished 16-of 26 for 290 yards, with one interception and one touchdown. "That's what you look for in a quarterback. This isn't the first time he's done it. He's done it in tough spots all year.

"I watched him go the length of the field in less than a minute to beat Tampa Bay. And that defense is as good as anybody's. Then, last week against Dallas, he was facing the No. 1 defense in the NFL. I like him, I don't really care if anybody else does.''

For the Rams, Saturday capped a stunning late-season turn of events. With one week to go in the regular season, St. Louis stood 12-3, held the NFC's No. 1 seed and home-field advantage in the playoffs, and were rolling with seven consecutive wins. But the Rams lost in Week 17 to lowly Detroit, slipped to the No. 2 seed, and then dropped their playoff opener, losing at home in the postseason for the first time since the franchise moved to St. Louis.

For the plucky -- some would say lucky -- Panthers, the ride just keeps getting sweeter by the week. Overtime is their element. And over time, we're all starting to appreciate just how good these Cats are.

"What it says is we have a heart of a champion, man,'' Carolina safety Mike Minter said. "To do this on the road, against that Rams team. We showed again we will not quit. We're going to fight. We've been doing it all year long, and we will not stop.''

There was no stopping them in St. Louis. On a day where everything seemed to go from wild to wilder, that wound up being our only certainty.

Don Banks covers pro football for SI.com.