PITTSBURGH — The Steelers are back to running the ball and playing exceptional defense. For one week, who needed Ben Roethlisberger?

Rashard Mendenhall ran 50 yards for a touchdown 2:35 into overtime and the Steelers overcame a shaky start by replacement quarterback Dennis Dixon and a missed field goal attempt late in regulation to beat the Atlanta Falcons 15-9 on Sunday.

With the Steelers leaning heavily on their retooled running game and defense without suspended star Roethlisberger, Mendenhall carried 22 times for 120 yards and the game's only touchdown. Hines Ward made six catches for 108 yards in his club-record 26th career 100-yard game.

Pittsburgh (1-0) appeared ready to win it with 39 seconds left in the fourth quarter, but Jeff Reed, who has nine career game-winning kicks, was wide right on a 40-yard attempt. Reed had hit earlier from 52, 36 and 34 yards.

Atlanta (0-1) was limited to three Matt Bryant field goals as the Steelers held former All-Pro running back Michael Turner to 42 yards on 19 carries.

The Steelers took a 9-6 lead on Reed's 34-yarder near the midpoint of the fourth quarter, following catches of 25 and 24 yards on successive plays by Ward. The Falcons tied it with 3:24 remaining on Bryant's third field goal, a 23-yarder, after deciding against going for it on fourth and a long 1 at the Pittsburgh 5.

It was the third overtime game in as many Falcons-Steelers meetings. They played a 34-all tie in 2002 at Heinz Field, and Atlanta won 41-38 at home in 2006.

Pittsburgh won its eighth consecutive season opener, the longest ongoing streak in the league. The Steelers also have won their past eight openers at home.

Predictably, the Steelers came out with a conservative game plan with Dixon making his second career start. Roethlisberger served the first game of his four-game suspension for violating the NFL's personal conduct policy and, because he is barred from all team activities, did not attend.

What was surprising was the Falcons played almost the same way as the don't-take-a-chance Steelers did, as evidenced by the 3-all tie at halftime and the 6-all tie at the end of the third quarter. Matt Ryan was 27 off 44 for an ineffectual 252 yards and was intercepted by Troy Polamalu late in the fourth quarter.

Roddy White made 13 catches for 111 yards, but the Falcons were within touchdown range only once, the drive late in the fourth in which they declined to gamble on fourth down.

Dixon finished 18 of 26 for 236 yards with an interception and had several other potential interceptions dropped. He wasn't good enough to win most games but, with the Steelers' defense back to its dominating ways, wasn't bad enough to lose this one.

Atlanta couldn't score until the final play of the first half, when Bryant made a 49-yarder to tie it at 3. Atlanta gained good field position when the Steelers gambled and Reed put a 55-yard attempt off the right upright with 17 seconds left.

The Falcons, 2-12-1 against the Steelers, took a 6-3 lead early in the third on Bryant's 39-yarder, which was set up by Tony Gonzalez's 20-yard reception — the 1,000th of his career. He is the first NFL tight end to reach that mark and the seventh receiver overall.

Dixon's one long completion of the day, a 52-yarder to second-year receiver Mike Wallace, led to Reed's tying 36-yard field goal Wallace is starting in place of former Super Bowl MVP Santonio Holmes, who was dealt to the Jets following a series of off-field issues.

Two Steelers starters went down with injuries, nose tackle Casey Hampton (hamstring) in the first half and left tackle Max Starks (left ankle) late in the third quarter. Neither returned, and their status for next week's game at Tennessee wasn't immediately known.