GLENDALE, Ariz. -- The final seconds ticked away and the Arizona Cardinals weren't sure how to celebrate. After all, it's been 33 years since the franchise last won a division title.
"My coach was like, 'Act like you've been there before, act like you've been there before,"' defensive tackle Darnell Dockett said. "I said 'Coach, I ain't been there before. I don't know how to act right now."'
Long the league's doormat franchise with just one winning season in the last 24 years, the Cardinals earned their first playoff berth since 1998 and first divisional title since they won the NFC East in 1975.
As NFC West champions, the Cardinals will host a playoff game for the first time since, as the Chicago Cardinals, they defeated Philadelphia to win the NFL title in 1947.
The players knew enough about celebrating to dump a bucket of ice water on Ken Whisenhunt, who has the team in the playoffs in his second season as coach.
"It was pretty cold, too," Whisenhunt said. "I was excited to get a bath. That's one of the things I guess as a coach you dream about."
Arizona's defense scored both of the team's second-half touchdowns, including a team record-tying 99-yard interception return by rookie Dominique Rodgers-Cromartie with 3:11 to play.
"He looked like a blur," Whisenhunt said.
Arizona (8-5) beat St. Louis (2-11) for the fifth straight time and extended the Rams' losing streak to seven games. After losses to the New York Giants and Philadelphia Eagles, the Cardinals improved to 5-0 against NFC West foes.
Michael Bidwill, the team's president and son of longtime owner Bill Bidwill, raised both fists in triumph as he trotted off the field. In the locker room, players donned T-shirts and hats with "NFC West Champions" emblazened on them.
Bidwill said his father "is very, very happy. This is the first time he's gotten a hat, you know. He likes his hat a lot."
Warner completed 24 of 33 passes against a Rams team he once led to a Super Bowl title. In the process, he reached 347 completions for the season, breaking the Cardinals' record of 345 set by Neil Lomax in 1984.
"If he's not the MVP in the league," Rams coach Jim Haslett said, "I'm sure he's in the top two or three."
Although Warner has no ill will toward the Rams, he did find it interesting the clincher came against his former team.
"My God's got a sense of humor," he said. "Maybe that's part of it."
Warner knows the team has made giant strides since he came to Arizona. He couldn't quite comprehend the significance considering the franchise's long, sorry history that preceded him.
"I was looking at some of the guys in the locker room that this may be their first year here or something, and a lot of guys are whooping and hollering in there," Warner said. "I just had to let them know that they don't know where we've been, just over the four years that I've been here how far we've come."
St. Louis defensive end Leonard Little was a teammate during Warner's glory years with the Rams.
"He's a leader," Little said. "He knows how to win because he was here winning with us for so long."
Jackson, who gained 64 yards on 19 carries in his second game back from a thigh injury, lost the ball on consecutive St. Louis possessions.
Arizona took a 14-0 lead on its first two series.
The worst rushing team in the NFL, the Cardinals gained 39 yards on the ground in a 10-play, 76-yard drive that ended with Tim Hightower's 1-yard TD run.
The Cardinals got the ball again late in the first quarter, but Warner's pass was intercepted by Ron Bartell and returned to the Arizona 6-yard line. Marc Bulger threw a 3-yard scoring pass to Jackson on the second play of the second quarter to cut the lead to 14-7.
Neil Rackers kicked field goals of 44 and 22 yards to put the Cardinals ahead 20-7 at the half.
Josh Brown missed a 44-yard field goal that would have cut the lead to 17-10 with 2:47 left in the half.
"The thing that disappointed me was the turnovers," Haslett said, "and the missed field goal disappointed me more than anything."
- Boldin topped 1,000 yards receiving in a season for a franchise-record fourth time.
- Hightower's 10 TDs rushing are a franchise record, breaking the mark of nine set by Ron Moore in 1993.
- Rams OT Alex Barron had his string of 47 consecutive starts end when he was benched for being late to a team meeting on Friday.
- Warner extended his franchise record with a TD pass in 21 consecutive games, longest active streak in the NFL.
- The Rams' Torry Holt moved into 12th on the NFL career receptions list.