GLENDALE, Ariz. -- So much for Carson Palmer's sore right elbow.
The Arizona quarterback completed 27 of 32 passes, 12 of them to Larry Fitzgerald, and the Cardinals ended an eight-game losing streak against NFC West foes by beating the St. Louis Rams 30-10 on Sunday.
Palmer, questionable for the game after being limited in practice last week, threw for 269 yards and a touchdown as the Cardinals (8-5) won for the fifth time in six games.
The Cardinals lost rookie safety Tyrann Mathieu in the third quarter with what coach Bruce Arians said "appears to be an ACL" injury to his left knee injury.
Arizona had not beaten an NFC West opponent since a victory over Seattle in the 2012 season opener. They had lost three in a row this season, including 27-24 at St. Louis in the opener.
Fitzgerald's 12 catches went for 96 yards, including a 7-yarder for a touchdown. It was his most receptions since he matched his career high with 13 against Seattle on Oct. 18, 2009.
Dansby had his second touchdown return of an interception in three games. He returned one 22 yards for a score in Arizona's 40-11 rout of Indianapolis two games ago.
Mathieu, the "Honey Badger" having a terrific rookie season, was hurt after returning the free kick that followed the safety with nine minutes left in the third quarter. He jogged toward the Arizona bench but his knee buckled and he collapsed, then he was carted off the field.
The Arizona safety came after a Cardinals punt was downed at the Rams 1-yard line.
On third down from the 5, Clemens retreated to the end zone and was hit by Abraham, who had three sacks on the day to give him 11 this season and move him into ninth on the NFL career sacks list with 133.
Arizona's Jay Feely missed two field goals, the first a 50-yarder, the second a 25-yard attempt with 4:27 to play.
In the first half, Palmer completed 16 of 17 for 169 yards and a touchdown and would have had another TD had Jim Dray not fumbled the ball at the half-yard line.
Limited in practice all week after injuring his elbow early in last week's loss at Philadelphia, Palmer completed his first 10 passes.
Fitzgerald had eight first-half catches, including the 7-yarder that put Arizona up 14-3 with 55 seconds left in the half.
Arizona took the opening kickoff and went 80 yards in eight plays, Rashard Mendenhall scoring on a 3-yard run.
The Rams responded with Greg Zuerlein's 44-yard field goal moments later.
St. Louis took the second-half kickoff and on its second play from scrimmage, Calais Campbell pressured Clemens as he threw. Dansby stepped in front of intended receiver Jared Cook, picked off the pass and ran untouched 23 yards for the score that made it 21-3.