ESPN NFL

NASHVILLE, Tenn. -- The Tennessee Titans aren't giving up on their slim playoff hopes, not without a fight.

Chris Johnson ran for 117 yards and two touchdowns and also took a short pass 66 yards for another score and the Tennessee Titans stayed alive by routing the woeful St. Louis Rams 47-7 Sunday. The Titans (6-7) must win out and get plenty of help after their 0-6 start, but they are focusing on what they control.

"Take one game at a time and worry about our next opponent," Johnson said.

The Titans started a three-game homestand by handing the struggling Rams (1-12) a fifth straight loss even with Vince Young sidelined by a strained right hamstring most of the game.

Young started despite an achy right knee and played well until pulling up at the end of a 44-yard run -- the longest of his career -- midway through the second quarter. He left with a 14-0 lead and watched from the sideline as Kerry Collins finished off the win.

Coach Jeff Fisher called the injury a mild strain. Whether Young plays next against Miami remains to be seen.

"We'll see," Young said. "I don't want to speak too fast. Right now I just want to go in, rehab it and get it back strong."

The Titans intercepted five passes they turned into 20 points, ruining the NFL debut of rookie Keith Null as St. Louis' third quarterback this season.

Rob Bironas kicked four field goals with a long of 50 yards, Vincent Fuller returned an interception 45 yards for a TD and Collins tossed a TD pass. Keith Bulluck and Cortland Finnegan had two interceptions apiece.

"We felt a third-string quarterback shouldn't come in and beat us if we stop the run and do the right things," Finnegan said.

Johnson, the NFL's leading rusher, became the fifth player in NFL history to reach 2,000 yards from scrimmage in his team's first 13 yards, joining Jim Brown, Walter Payton, O.J. Simpson and Priest Holmes.

Johnson also set a couple of franchise records as his 17-yard run at the end of the first half pushed him past Hall of Fame running back Earl Campbell's mark of 1,981 yards from scrimmage in 1980. Johnson also has the team mark with eight straight 100-yard rushing games, breaking his tie with Campbell at seven.

His 17-yard run at the end of the first half pushed him past Hall of Fame running back Earl Campbell's mark of 1,981 yards from scrimmage in 1980. Johnson also has the team mark with eight straight 100-yard rushing games, breaking his tie with Campbell at seven.

Johnson has 1,626 yards rushing and remains on pace to finish with 2,001 yards at this rate.

Steven Jackson came in second only to Johnson in rushing. Tennessee held the Rams' top offensive threat to a season-low 47 yards on 19 carries. Jackson was visibly upset after the game.

"Instead of standing here embarrassing myself, and my family, I'm just going to say I'm tired. I'm just tired. I'm tired. You fill in the blanks. However you want to write the article, however you want to say it, I'm just tired," Jackson said before walking away from his locker.

Kyle Boller had been limited in practice with a sore thigh. No lineup change was announced before Null took the field for the Rams' first series for his first NFL snaps even though St. Louis coach Steve Spagnuolo said earlier this week he hoped not to use the sixth-round pick this season.

But Boller couldn't push off the leg in pre-game warmups, so Null started. Spagnuolo wouldn't commit to which quarterback will start next week. Null started well enough, completing 7 of his first 8 passes for 42 yards. Then it went downhill, and he finished 27 of 43 for 157 yards.

"You put a guy in a tough situation, but Keith's pretty solid. He's got some resolve, so I'm going to hope that he will be able to shake it off," Spagnuolo said.

The Rams did score a rare TD when Null found Randy McMichael with an 11-yard pass in the fourth quarter, a score set up when Spagnuolo called a fake punt on fourth-and-7. Kenneth Darby had a big hole as he ran 51 yards to the Tennessee 13.

Right guard Richie Incognito didn't help the Rams either, picking up personal fouls for head-butting Sen'Derrick Marks in the first quarter and for pushing over Fuller after a play ended. Titans defensive end Kyle Vanden Bosch pushed Incognito over with a hand, and a flag flew. The 15-yard penalty went to Incognito. The Rams were flagged 10 times for 82 yards.

The Titans were much sharper including Young, who posted a perfect passer rating in the first quarter at 158.3 as he completed five of his first six passes for 132 yards with a TD. He showed no signs of a balky knee as he moved around and even took off running.

But Young pulled up at the end, grabbing at the back of his right leg. He went into the locker room and watched the second half from the sideline with a ballcap turned backward.

Collins, benched for Young after that winless start, came in and kept the scoring going. The Titans led 33-0 before the Rams avoided the shutout.

Game notes

The Titans matched the most points scored since a 47-10 win at Detroit on Thanksgiving 2008. ... Fuller's interception return was the fourth of his career for a TD. ... Collins' TD went to Alge Crumpler, the tight end's first touchdown since Oct. 5, 2008, at Baltimore. ... The Titans have won eight straight over NFC opponents. ... Titans LB David Thornton hurt a shoulder and did not return. ... This is the seventh time this season St. Louis has been held to 10 or fewer points.