The Tennessee Titans aren’t about to be distracted by a power outage in their locker room or a struggling opponent.

Not now. Not as a division champion.

Kerry Collins threw two touchdowns, and Chris Johnson ran for 136 yards and a score as the Titans routed the Cleveland Browns 28-9 Sunday to grab the AFC South title for the first time since 2002 in what they hope is the first of many goals reached this season.

‘‘Obviously, we’re all pleased and happy we won the division,’’ Collins said. ‘‘We know there’s a lot of things left we want to accomplish. Today was a good first step.’’

The Titans have won 15 of their last 16 games, and are the first team to secure a postseason berth this year. They maintained at least a two-game lead with three to play for home-field advantage in the AFC playoffs and clinched a first-round bye when San Francisco beat the New York Jets 24-14 later Sunday.

A subdued celebration featured players dumping a cooler of water over coach Jeff Fisher for the Titans’ second consecutive playoff berth, secured with the franchise’s best record through 13 games, 12-1. Fisher credited his Titans’ 10-0 start with helping them wrest the division away from the Indianapolis Colts.

‘‘It’s a rewarding feeling. Our goal when we left the playoff game in San Diego, the day we came back, was to have a home playoff game this year. That was our first goal, first and foremost. We’ve now guaranteed that. We’ll move onto the next step hopefully,’’ Fisher said.

The Titans were a bit like a videoboard that didn’t work thanks to a blown transformer that knocked out all but four emergency lights in their locker room. They turned it over three times, with LenDale White losing his first fumble this season, and they had a season-high 13 penalties for 131 yards.

Defensive tackle Albert Haynesworth said he didn’t even notice the power even after dressing in near darkness.