ST. LOUIS — The dome was rocking with chants of “Let’s Go Bears,” and Chicago’s football team looked right at home in St. Louis — especially high-stepping rookie Devin Hester.

Hester set an NFL record with his fifth and sixth returns for touchdowns, a 94-yard kickoff runback in the second quarter and a 96-yarder in the final period Monday night. That sparked a 42-27 victory over the Rams.

The NFC North champions (11-2) clinched a bye for the first week of the playoffs as beleaguered quarterback Rex Grossman had a solid effort and the running attack dominated the second half.

But it was Hester who made the thousands of Bears fans who trekked from Chicago rise from their seats.

A second-round draft pick, he also has three punt return touchdowns and ran back a missed field goal 108 yards against the Giants to tie the longest play in NFL history. But he’d returned only six kickoffs all year before his historic romps.

He headed up the middle on the first, then swiftly cut to his left untouched and sped down the sideline, high-stepping like a drum major the last few yards while holding up the football for the raucous Bears fans.

Hester outdid himself in the fourth quarter when it appeared the Rams might try an onside kick. The only Bear standing deep, he went straight up the center of the field, again untouched, and turned around at the Rams 20 looking for pursuers. No one was there.

Hester struggled to find a position in college at Miami, but he’s been a sensation with the ball in his hands on kick returns for the Bears.

Carrying a 14-13 lead into the second half, the Bears outgained the Rams (5-8) 191 yards to 31 in the third quarter. They scored on Thomas Jones’ 30-yard run and Muhsin Muhammad’s superb fingertip catch of a 14-yard pass from Grossman, who probably quieted calls for his benching — particularly from the thousands of fans who outshouted Rams rooters much of the evening.