KANSAS CITY, Mo. — NFL pass rushers are a lot like sharks. That was the attitude of the Kansas City Chiefs’ defense in the second half of the team’s 34-7 beating of the St. Louis Rams on Sunday afternoon at Arrowhead Stadium.

With a second-half lead, a Rams offensive line losing starters in every quarter and inexperienced quarterback Austin Davis in the St. Louis pocket, the Kansas City defense knocked him down seven times, allowed only 116 net passing yards and dominated the game as the Chiefs pushed their record to 4-3 on the season.

“The defense absolutely dominated the game,” Chiefs quarterback Alex Smith said of his defensive teammates. “To have a defense play like those guys did today is special. They really dominated and set the tone.”

Setting the tone for the Chiefs defense was outside linebacker Justin Houston. He added three sacks to the seven he carried into the game to give him 10 in seven games. That’s halfway to the franchise sack record set by Hall of Fame linebacker Derrick Thomas in 1990.

“This was a game where those sacks came from the whole defense,” Houston said. “There was great coverage from the secondary and linebackers and that forced the quarterback to hold the ball and that allowed us to get to him.”

While the defense stifled the Rams’ offense, the Chiefs were also getting major contributions from the other parts of their game. Backup running back Knile Davis returned the second-half kickoff 99 yards for a touchdown and Cairo Santos added two field goals, including a career-long 53-yard kick. Offensively, they had three rushing touchdowns, including two from running back Jamaal Charles and Smith completed 24 of 28 passes for 226 yards, connecting six times with wide receiver Dwayne Bowe. In all, the Chiefs scored 34 unanswered points.

The Rams generated only 200 yards of offense, falling to 2-5 and they left Kansas City with a roster decimated by injuries. By the fourth quarter, only one offensive line starter was in the same position at which he opened the game and an injury-riddled secondary was minus the two safeties that started the game.

It was a frustrating loss for a Rams team that beat the defending Super Bowl champion Seattle Seahawks just a week ago.

“To beat a Super Bowl champion and then come in and perform like we did today is not what we want,” said defensive end Robert Quinn.

Austin Davis led the Rams to a touchdown on the first possession of the game, rolling 65 yards on six plays capped by a 1-yard touchdown toss to tight end Lance Kendricks. The key play in the drive was a 43-yard pass play from Davis to wide receiver Kenny Britt on third-and-1.

“We started fast but we didn’t finish,” said Rams head coach Jeff Fisher. “This team is going to have to learn to play consistent through 60 minutes.”

The Chiefs tied the score with a 10-play, 53-yard drive that lapped over the end of the first quarter and start of the second. A 17-yard pass from Smith to tight end Travis Kelce took the ball to the one-yard line, setting up the score as Charles blasted through the left side.

St. Louis had a great opportunity in the second quarter when Charles fumbled and the ball was recovered by Rams defensive end William Hayes at the Chiefs 8-yard line. Two running plays netted St. Louis two yards and on third-and-goal, Davis was sacked by Chiefs safety Ron Parker for a 14-yard loss.

That set up a 38-yard field goal attempt for Greg Zuerlein, but he pushed his kick wide right and the Chiefs escaped.

“That was the play of the game,” Smith said. “To give them that opportunity and then the defense goes out and stones them. That established the tone for the rest of the game.”

Santos hit his 53-yard field goal with one second left in the first half, only after overcoming a false start penalty and consecutive sacks by Quinn to get those three points on the board and carry a 10-7 lead to intermission.

Knile Davis, who had a 108-yard return last season against Denver, sparked Kansas City’s second-half surge with the Chiefs’ first return score of the season. Santos added a 28-yard field goal near the mid-point of the third quarter and the Kansas City lead grew to 20-7.

A pair of fourth-quarter touchdown runs — 36 yards by Charles and 3 yards from Davis — capped the scoring. Houston and his mates continued to swarm and picked up three more sacks to give them seven on the afternoon.

“You can see what the conditions are,” Houston said. “They were forced to pass and any time that happens, as a pass rusher you are trying to take advantage. I really didn’t pay attention to their problems (injuries). I just kept working to get some pressure on him.”

What the Chiefs said:

“This whole season, we’ve been one or two blocks from getting it into the end zone. It was good to see today when everybody executed. Right before we went out, Coach (Dave Toub, the special teams coordinator,) was like ,’Man, we’re overdue for one.’ We ended up busting that one. It was pretty neat.” — Running back Knile Davis, on his 99-yard kickoff return touchdown to open the second half.

What the Rams said:

“We clearly got outplayed in the second half of this game, in all three phases. It probably started before half when we had the turnover, got sacked and got no points. … We gave up against the run, we gave up a high completion percentage, and we gave up too many third downs.” — Coach Jeff Fisher.

What we learned about the Chiefs:

1. The Chiefs’ offense contributed three touchdowns, none from the wide receivers. Through seven games, the Kansas City wideouts have not caught a touchdown pass. However, veteran wide receiver Dwayne Bowe is getting more involved in the passing game, as he led the team with six catches for 64 yards Sunday. “I miss the end zone, I can’t lie,” Bowe said. “But all that matters is we win, and we did that today.”

2. The Kansas City defense has yet to allow a rushing touchdown this season. The Chiefs are the only team in the league that can make that claim. “That’s an important part of what we’re getting done,” veteran defensive end Kevin Vickerson said. “If you can keep them out of the end zone, you are going to win games.”

–OLB Justin Houston had three sacks in Sunday’s game, giving him 10 on the season and 36.5 in his career. In just his fourth season, he is already in the Chiefs’ top-10 list of sackers. Against St. Louis, Houston’s sacks helped him jump ahead of DE Wilbur Young (35).

–RB Jamaal Charles scored two running touchdowns against St. Louis on Sunday. Since the start of the 2013 season, he has 25 TDs, more than any other offensive player in the league. He is ahead of Denver TE Julius Thomas (21), Seattle RB Marshawn Lynch (20) and Denver WR Demaryius Thomas (20).

–QB Alex Smith completed 24 of 28 passes (85.7 percent) against St. Louis, the best single-game performance in Chiefs history. Smith connected with eight receivers and finished with 226 passing yards.

What we learned about the Rams:

1. Coach Jeff Fisher will have problems fielding an offensive line in the next few weeks as the Rams go on the road for two more games. When Sunday’s game started, the offensive line consisted of left tackle Jake Long, left guard Greg Robinson, center Scott Wells, right guard Rodger Safford and right tackle Joe Barksdale. When the fourth quarter started, the line looked like this: left tackle Robinson, left guard Davin Joseph, center Barrett Jones, right guard Mike Person and Barksdale. Early indications are that Long torn a knee ligament.

2. Injuries are also going to be a major problem for the Rams’ secondary over the next few weeks. St. Louis had three defensive backs on its seven-man inactive player list for Sunday’s game: cornerback Janoris Jenkins, cornerback Trumaine Johnson and safety Maurice Alexander. During the game, the Rams lost safeties Rodney McLeod (knee) and Cody Davis (concussion). Cornerback E.J. Gaines left the field at one point but returned to action. With the upcoming schedule featuring three more road games in the next four and contests against the San Francisco 49ers, Arizona Cardinals, Denver Broncos and San Diego Chargers, there is no time to get well.

–LT Jake Long sustained what appears to be a torn knee ligament, and the rest of his season could be in jeopardy. Long went down late in the third quarter and had to be helped off the field. Rams coach Jeff Fisher indicated the seriousness of Long’s injury will not be known until Monday.

–TE Jared Cook entered Sunday’s game against Kansas City as the Rams’ leading receiver. By the time the smoke cleared at Arrowhead Stadium, Cook had just one catch for 11 yards. He was targeted three times and was effectively taken out of the St. Louis passing game, largely because he was held in to help with pass protection.

–DE Robert Quinn picked up sacks on back-to-back plays in the first half, giving him three on the season. Overall, the Rams have only six sacks in seven games.