ST. LOUIS — The World Series champion St. Louis Cardinals were treated to a raucous victory parade through downtown Sunday afternoon, just two days after winning their 11th title.

They should have taken the city’s NFL team, the Rams, along for the ride.

The Cardinals’ celebratory parade cranked up about 45 minutes after the struggling Rams, 0-6 going into Sunday’s game with the New Orleans Saints, pulled off a 31-21 shocker in the Edward Jones Dome.

The bad thing for the Saints is Sunday’s game really wasn’t that close as they trailed 17-0 at halftime and 24-0 in the third period, their largest deficit of the season, despite coming off a 62-7 blowout of the Indianapolis Colts.

“They (the Rams) certainly played with more energy than we did,” Saints coach Sean Payton said after watching from the coaches’ booth high above the field. “It’s interesting when you sit up there, you kind of get a different take on things — and I just thought we looked flat.

“Credit St. Louis,” he said, “they came out and ran the ball well and made enough plays to win offensively and defensively. They pretty much handled us all day. It’s been awhile since that’s happened.”

The Saints (5-3) were handled offensively as they finished with a season-low 283 total yards — 99 fewer than their previous low of 382 yards in a Week 2 win over Chicago — and allowed six sacks for the first time in Payton’s 88-game regular-season tenure.

The Saints also turned the ball over twice and had a punt blocked, and the defense was rocked for 323 yards with Rams running back Steve Jackson piling up 191 of them — rushing for 159 yards and two 3-yard touchdown runs on 25 carries and catching four passes for 32 yards.

“We struggled blocking, we struggled running the ball and we struggled (pass) protecting,” Payton said. “When we did, we didn’t have a lot going for us. And it’s disappointing.”

Remember, this is a Rams team that:

• Scored just five touchdowns all season and had four Sunday.

• Had not scored more than 16 points in a game this season, which they eclipsed with 17 first-half points Sunday.

• Trailed at halftime of their first six games by an average of 15.7 points, including double-digit deficits of 10, 14, 15, 21 and 27 points.

• Allowed 294 rushing yards a week before in a 34-27 loss to the Dallas Cowboys until holding the Saints to 56 yards on 20 attempts.

On top of that, the Saints were shut out in the first half since Week 2 of the 2007 season when they dropped a 31-14 decision to the Tampa Bay Bucs in Tampa.

“I thought we had a good week of practice,” said Saints guard Carl Nicks. “We didn’t think we’d come here and be flat. Things just didn’t go well. The Rams played a helluva game, and at the end of the day, they just whipped us. It was pretty simple.”

Saints tackle Jermon Bushrod said it was hard to fathom, especially coming off the record-setting victory over the Colts just one week earlier.

“This is the NFL, man, and these (wins) are hard to come by,” he said. “Sometimes they’re going to be like they were last week and sometimes you’re going to have to fight. You have to fight to be consistent, especially on the road.”

The Saints were anything but consistent, especially in the first half. They had just seven first downs and 94 total yards on 31 plays with Drew Brees being sacked three times for a total of 26 yards in losses.

The defense played well enough to keep it close in the first half, trailing just 3-0 on Josh Brown’s 38-yard field goal with less than two minutes remaining in the second quarter.

“I don’t think we came out flat,” said defensive end Will Smith, who had two of the Saints’ four sacks. “With about two minutes left in the first half, it was three to zip.”

But that’s where the game turned as the Rams scored two touchdowns in 53 seconds of clock time, the first on a 3-yard run by Jackson and the second on an 8-yard pass from quarterback A.J. Feeley, who was filling in for an injured Sam Bradford, to wide receiver Brandon Lloyd.

The first score was set up when Rams defensive end Robert Quinn overpowered Saints safety Jonathon Amaya to block a Thomas Morstead punt at the Saints’ 15. The second came when Rams cornerback Josh Gordy intercepted Brees at the New Orleans 38 on the first play after Jackson’s TD.

“The sequence at the end of the second quarter hurt us,” Payton said. “I think this whole time we felt at some point we would be able to maybe get some momentum and get back in the game.

“But the blocked punt leads to a touchdown, the interception leads to a touchdown — and now, your margin for error has just tripled.”

“We definitely weren’t playing our game,” tight end Jimmy Graham said. “The thing is, it’s 3-0 with two minutes left in the first half and we started giving away points with the punt block and then turned the ball over. We have to get better at the little things.”

The Saints futilely tried to come back in the second half after Jackson had his second 3-yard TD blast to make it 24-0.

Feeley fumbled when he was sacked by Saints safety Malcolm Jenkins, and linebacker Jonathan Vilma recovered in the end zone. Pierre Thomas cut the deficit to 10 points at 24-14 when he scored on a 3-yard run in the fourth.

But the Rams iced it when safety Darian Stewart intercepted Brees and returned it 27 yards for a touchdown with 2:51 remaining in the game.

An 8-yard scoring pass to wide receiver Lance Moore with six seconds remaining ended an off day for Brees, who completed 30 of 44 passes for 269 yards with two TDs and finished with a passer rating of 73.0.

“As you look at some of the cardinal sins of football, we committed quite a few of those today,” Brees said. “That’s getting a punt blocked deep in your territory before the half and then my interception before the half. So we gave them 14 points going into halftime to make it 17-0.”

“Obviously, it’s a disappointing loss,” Payton said. “Our hats are off to those guys, they did a good job. They outplayed us today, it was clear.”