GLENDALE, Ariz.—Chicago's defense outscored Arizona all by itself on a day when the Bears had to win to keep their playoff hopes alive.
It was the third pick Tillman has brought back for a touchdown this season and the eighth overall by Chicago, one shy of the NFL record.
Brandon Marshall caught six passes for 68 yards and a TD, breaking the Bears franchise record for yards receiving in a season in the process.
Chicago (9-6) snapped a three-game losing streak and won for just the second time in seven tries. The Cardinals (5-10) lost for the 10th time in 11 games.
To make the playoffs as a wild card, the Bears must win at Detroit in their regular-season finale next Sunday, then have Minnesota lose to Green Bay or have Seattle lose its final two games. The Seahawks were home against San Francisco Sunday night.
Matt Forte gained 88 yards in 12 carries, including a 4-yard TD run, for Chicago before leaving with an ankle injury early in the second half.
Jay Cutler completed just one of his first 11 passes, then went 5 of 5 on a touchdown drive in the final minutes of the first half. He finished 12 of 26 for 146 yards and a touchdown.
It was the defense's dominance of Arizona's NFL-worst offense that determined the outcome.
The Cardinals continued to search for someone to move the ball.
After he threw the interception to Tillman put Chicago up 28-6 on Arizona's first offensive series after halftime, rookie Ryan Lindley was benched in favor of Brian Hoyer, claimed off waivers from Pittsburgh 13 days earlier.
Kelvin Hayden picked off Hoyer's pass late in the game and returned it 39 yards to the Arizona 10.
Arizona's Larry Fitzgerald caught eight passes for 111 yards, just his second 100-yard receiving game of the season. The first was in Week 3 against Philadelphia when the Cardinals were off to a 4-0 start.
Marshall made a diving grab of Cutler's long pass at the Arizona 14 early in the game, but Cardinals coach Ken Whisenhunt threw the challenge flag before the Bears could get the next play off. After the review, the pass was ruled incomplete.
No matter, the Bears scored a moment later anyway.
Chicago pinned the Cardinals deep and, on second-and-11 from the 3, Beanie Wells' right knee gave way and he dropped the ball as he went backside first to the ground. Bowman grabbed it and skidded over the goal line for the first touchdown for the Bears defense since Nov. 4.
Fitzgerald's leaping grab of Lindley's 18-yard pass helped set up Jay Feely's 49-yard field goal that cut it to 7-3.
But Forte rambled 36 yards on the final play of the first quarter and Cutler threw 30 yards to Marshall to the Arizona 4—the Bears quarterback's first completion of the game in seven throws. Forte carried it in from there and Chicago led 14-3.
Arizona's defense forced a Bears punt from their 6, and the Cardinals took over at the Chicago 32. But Lindley threw three errant passes, and a fake field goal of what would have been a 50-yard attempt went nowhere.
Chicago soon gave Arizona another chance when Dave Zastudil's punt careened off the Bears' D.J. Moore and bounced into the hands of the Cardinals' Michael Adams. Adams raced to the end zone but, as a muffed punt, it was brought back to the Chicago 36. Arizona advanced to the 18 before Feely's 35-yard field goal cut the lead to 14-6 with 2:18 left in the half.
That was plenty of time for Cutler, who after completing one of his first 11 passes, went 5-for-5, capped by an 11-yarder to a wide open Marshall, to put the Bears up 21-6 with 19 seconds left in the half. The highlight of the drive was a diving grab of Cutler's 35-yard pass by Alshon Jeffery.
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