By Steve Keating

CLEVELAND (Reuters) - Ben Roethlisberger threw for a pair of touchdowns and Rashard Mendenhall ran for two more as the Pittsburgh Steelers crushed the Cleveland Browns 41-9 on Sunday to clinch the AFC North and a first-round playoff bye.

The Steelers (12-4), who entered the last weekend of the regular season having already locked up a playoff spot but needing a victory over their bitter rivals to secure an easier path to the Super Bowl, came out with guns blazing.

"Not a lot needed to be said about the stakes. It's one less game we have to play to get to where we want to go."

On a bitterly cold day, Pittsburgh's offense was scorching hot, seizing control of the contest with a pair of touchdowns in the opening eight minutes.

Pittsburgh's top-ranked defense was also in ferocious form, intercepting rookie quarterback Colt McCoy three times in the opening half with Roethlisberger converting the turnovers into two touchdowns and a field goal.

After sitting out two games with an Achilles tendon injury, Steelers Pro Bowl safety Troy Polamalu was pressed into action for the crucial contest and made an immediate impact by picking off McCoy to snuff out Cleveland's (5-11) opening drive.

On the next play, Roethlisberger dropped back and hit Mike Wallace with a 56-yard touchdown strike on Pittsburgh's first play from scrimmage.

Roethlisberger hooked up with Wallace on Pittsburgh's next possession with a 41-yard pass that set up a one-yard touchdown plunge by Mendenhall.

"It helps when you score on the first offensive play," said Roethlisberger. "Mike is so fast that I can just throw it out there and he can do the rest for me.

"We like to get on top and put a dagger in them early."

Down 14-0, the Browns did not appear ready to wave the white flag, McCoy marching his team down to the Pittsburgh two, but the Steelers defense would not break and forced Cleveland to settle for a 19-yard Phil Dawson field goal.

The Steelers answered with a 74-yard drive capped by Mendenhall diving over for his second score of the game.

The Pittsburgh defense continued to apply pressure, Ryan Clark intercepting McCoy to set up a four-yard Roethlisberger touchdown pass to Heath Miller that put the visitors up 28-3 three plays later.

Shaun Suisham hit a 41-yard field goal to cap a first-half rout that sent bone-chilled Cleveland fans to the exits.

Pittsburgh added to their lead in the second half with a bit of razzle-dazzle, Antwaan Randle El tossed a three-yard touchdown pass to fellow wide receiver Hines Ward.

Suisham also added another field goal before the Browns mustered a late consolation score in a near-empty stadium.

(Editing by Frank Pingue)