ST. LOUIS — Like any other game, Mike Zimmer took a little Pepto-Bismol to calm the stomach. It was business as usual, even if it was his first time calling the shots.

“Honestly, it wasn’t that bad,” the Minnesota Vikings’ new coach said after beating the St. Louis Rams 34-6 and getting a celebratory ice bath on Sunday.

“I felt good about the game, I felt good about the game plan, I felt good about the players, felt good about how we practiced,” the 58-year-old Zimmer said. “I was probably more nervous for the first preseason game.”

The Vikings were 4-0 in the preseason and they opened with a bang, too. Wide receiver Cordarrelle Patterson ran for 102 yards on just three carries, with a 67-yard scoring run off a simple pitchout the backbreaker, and the defense stuffed a team down to its third quarterback after the first half.

“We hear about their defense all the time, especially their front four,” Patterson said. “The offensive lineman did a great job of standing them up and I say hats off to those guys.”

Zimmer was a defensive coordinator with Dallas, Atlanta and Cincinnati the previous 14 seasons and inherited a 5-10-1 team. A defense that surrendered the most points in the NFL last year clicked right away, holding St. Louis to 170 yards the first three quarters.

Reasons why Zimmer’s debut was a smash success and the Rams are reeling from a 28-point margin that matches the best in franchise history for an opener set in 1937:

Naturally, the Rams keyed on Adrian Peterson. They held him down just fine, holding the Vikings star to 75 yards on 21 carries. But they got burned big-time by Patterson, who broke at least four tackles on the game-breaking 67-yarder that made it 20-3. He had carries of 23 and 12 yards in the first half to go with three receptions for 26 yards.

“He’s a tremendous talent,” Peterson said. “As soon as he got that pitch and I saw that great block by Matt (Kalil) I pretty much threw my hands up.

“I knew he had the ability to take it the distance.”

Shaun Hill stood on the sideline with arms crossed far away from the action most of the second half and deferred injury updates to coach Jeff Fisher. The Rams signed Case Keenum last week but if Hill can’t go, Austin Davis will make his first career start next week at Tampa Bay.

Davis, who backed up Kellen Clemens the last nine games in 2013, was 16 for 23 for 192 yards in his NFL debut. But he had an interception returned 81 yards by Harrison Smith for a tack-on TD late in the game.

As a rookie in 2012, Blair Walsh kicked three field goals of 50-plus yards in a victory at St. Louis. He got the Vikings on the board early with a 52-yarder and added a 46-yarder in the opening minute of the second quarter. That was the only scoring before the Vikings capitalized on Josh Robinson’s interception and Matt Cassel threw an 8-yard TD pass to Greg Jennings just before halftime.

Rams kicker Greg Zuerlein had been 7 for 13 from 50-plus before hooking a 50-yarder in the first quarter. He later connected from 56 and 46 yards.

Rams offensive lineman Greg Robinson was the second overall pick of the draft and was supposed to open the season as a starting guard. He alternated at guard and tackle throughout training camp, partly as insurance in case Jake Long wasn’t ready coming off a knee injury. So far, he’s mastered neither spot. He filled in at guard after Rodger Saffold left with a neck injury in the fourth quarter, but before that had been used only on special teams.

Understandably, the Vikings’ locker room was exuberant. Defensive end Everson Griffin, who had two sacks, gushed that his team had “the best game plan in the world.” But Zimmer was careful not to get carried away.

“They played well today,” the coach said. “That was today and next week will be a different week.”

Even after losing Bradford, the Rams had been optimistic about a breakthrough season. They were far too sloppy in the opener with 13 penalties for 121 yards along with numerous missed tackles, and Vikings fans drowned out the few thousand partisans who stuck it out.

“I told the team this is not going to define our season, it’s just the opener,” Fisher said. “We’ve got work to do.”