Early this week, Vikings coach Mike Zimmer made it clear the home crowd at U.S. Bank Stadium could make a big difference in the Vikings being able to beat a Rams, a team with the No. 1-ranked offense in the NFL and one predicted by many analysts to upset the Purple.

Vocal fans gave Zimmer the volume he wanted, which he said made it difficult for the Rams to get their offense going or make audibles at the line of scrimmage in Sunday's 24-7 victory for the Vikings.

"I think the crowd was huge," Zimmer said. "They stifled [the Rams'] no-huddle offense and made the communication hard and made them use a couple of timeouts. They even started huddling some.

"They were trying to communicate, and I don't think they were prepared for the crowd noise we had. It was good. The crowd was outstanding."

The halftime score was 7-7 because safety Anthony Harris, starting in place of the injured Andrew Sendejo, made a game-changing forced fumble and recovery at the goal line to keep seven points off the board with 4:03 left in the second quarter. The Vikings didn't score off the turnover, but they came out in the third quarter looking like a completely different team.

The Rams offense was moving the ball well early, going 75 yards in nine plays for an opening-drive touchdown.

"We didn't play very good on that first drive," Zimmer said. "We messed up the third down and allowed them to get going. We didn't play the run very good. We got out of our gaps. We just had to clean it up and get back to doing what we do."

Zimmer talked about the difference between the two halves.

"We came out in the second half [and] we had a good idea of what they were doing after a while," he said. "Once we figured it out, then I kind of knew what we had to do to change things up. The players executed. They did a good job. I thought we did a good job in coverage [Sunday]. We did a good job against the run. It was nice."

Zimmer had a lot of good things to say about running back Latavius Murray, who had 15 carries for 95 yards (6.3 yards per carry) and two touchdowns.

He also had high praise for wide receiver Adam Thielen, who put the game on ice with a 65-yard touchdown catch-and-run with 10:14 remaining in the fourth quarter. Thielen finished with six receptions for 123 yards.

Another difference-maker on offense was tight end Kyle Rudolph, who had five catches for 58 yards. Four of those receptions were for first downs.

In my opinion, this is the best game the Vikings have played this season, and maybe even all of last season.

But Zimmer says the team still hasn't played its best. He knows the next three contests will be tough, with road games starting Thanksgiving at Detroit, followed by going to Atlanta and Carolina.

"It will be tough, but they're all tough. [Sunday] was tough. Last week was tough," Zimmer said. "But I think we have a tough football team and we just have to keep playing the way that's allowing us to do the things we're doing."

No time to change

There has been a lot of talk about Teddy Bridgewater coming back to play this season, but how and why would you replace quarterback Case Keenum? Keenum played only his fourth-best game from a quarterback rating standpoint (100.8) against the Rams but still was 27-for-38 for 280 yards and one touchdown with no interceptions.

Keenum's three highest ratings were a 142.1 against the Bucs on Sept. 24, a 117.0 against the Redskins on Nov. 12 and a 110.3 against the Bears on Oct. 9.

But Sunday was his most crucial game, going against his former team that was 7-2 and crushing everyone it faced.

After the game, Keenum was asked how he keeps performing well with all of the questions about whether he should remain the starter.

"I don't know," he said. "Well, for one, I don't listen. I don't listen to what is going on. I don't pay attention to a lot of those things that don't matter to me, that don't matter to how I play. I go out and do my job. … I know these opportunities don't come along very often. I'm not going to sit around and worry and wait and try to figure things out.

"That is not fair to the rest of my team if I do that, because I'm not at my best if I'm using a percentage of my mind and worrying about other things."

I'm convinced Keenum, barring an injury, will be the starter for the rest of the season and maybe even signed for next year.

"If it is not broke, don't fix it," he said. "Let's keep doing what we're doing."

Keenum noted the great protection he's been given by the Vikings' offensive line. He hasn't been sacked in six games, and the Rams have one of the best defensive lines in football.

On his touchdown pass to Thielen, Keenum said the whole offense came together to make that play.

"They were in cover zero so they were blitzing a lot of guys, and that doesn't leave a free safety in the middle of the field to help," Keenum said. "We had a great play call, [offensive coordinator] Pat [Shumur] did a great job, the offensive line did a great job because they're bringing more than we can actually block, and gave me enough time to find him," he said. "Quick little throw, and that's what happens."

Keenum, who remains an unsung hero, is now the sixth Vikings quarterback to throw for 2,000 or more yards in his first season with the team. He's tied Bridgewater's mark for most victories in his first season with six, even though he should have gotten credit for the win over the Bears that went to Sam Bradford, who was limited because of an injured knee and replaced by Keenum in the second half.

Dominated game

The Vikings rushed for 111 yards and passed for 100 yards in the third quarter alone, while the Rams were held to only 23 rushing yards and 23 passing yards.

The defense held great Rams running back Todd Gurley to a season-low 37 rushing yards and only 19 receiving yards, his third-lowest total on the season. Twenty of those rushing yards came on the first drive of the game on four carries. The rest of the way they held him to 17 yards on 11 carries.

Vikings linebacker Eric Kendricks, who had five tackles and two quarterback hits, talked about stopping Gurley.

"We just played our keys, just played team defense," he said. "That's what it's always about. We have a bunch of guys who are thirsty and angry to be successful as a team. It's fun to be a part of."

Sid Hartman can be heard on WCCO AM-830 at 8:40 a.m. on Monday and Friday and at 9:30 a.m. on Sundays. E-mail: shartman@startribune.com