ST. LOUIS — Without his favorite target, Sam Bradford seemed lost. The top pick of the 2010 draft completed a measly seven passes.

The St. Louis Rams defense was there to pick him up — by continually knocking down Kevin Kolb.

The Rams (3-2) totaled nine sacks, their most since 1998, in a 17-3 victory Thursday night that ended the Arizona Cardinals’ early unbeaten run.

“They’ve played great all year,” Bradford said. “They’ve kept us in a lot of games. Fortunately, we were able to make the big play in the fourth quarter to go up two scores, but all the credit tonight to our defense.”

Danny Amendola made a spectacular one-handed grab for a 44-yard gain on an underthrown ball that set up Bradford’s touchdown pass to Lance Kendricks’ on the Rams’ opening drive.

Bradford misfired on five consecutive passes before Amendola injured his right shoulder making a diving attempt on a 22-yarder that was initially ruled a catch but was overturned after the Cardinals challenged. Amendola used his left arm to fling his helmet on the way to the X-ray room and had his arm in a sling after the game, when he was not made available to reporters.

Bradford had six more incompletions plus an end zone interception by Patrick Peterson before ending the slump with a 52-yard touchdown pass to rookie Chris Givens for a 14-point cushion early in the fourth quarter. Givens, the fastest player on the team, had dropped a few passes earlier in the game.

“I don’t know how wide open I was,” Givens said. “But I knew I was going to be open.”

The Cardinals outgained the Rams 282-242. But St. Louis made all the big plays.

Robert Quinn had three sacks, and six others had one apiece. Rookie cornerback Janoris Jenkins had three pass breakups.

“We know we can be a dominant defense,” said Quinn, a first-round pick last year. “We don’t try to talk too much. Just go out there and execute, and let our play do the talking for us.”

Arizona (4-1) scored at least 20 points in each of its first four games, but had no luck containing a pass rush that had totaled just six sacks on the year and got stopped twice inside the 20 in the final minutes. The Rams also had a strong defensive game last week.