Hopkins is certainly off to a good start.
Coach Gary Kubiak said Johnson was being evaluated for a concussion.
"We survived today because of some great heroics and plays by him," Kubiak said of Hopkins.
When Hopkins saw the coverage on the game-winning touchdown, he couldn't wait for Schaub to snap the ball.
"Anytime I see a one-on-one that's a wide receiver's dream," he said. "He put it in the perfect position for me to go up and catch it. We practice that basically every day and practice makes perfect."
The Texans (2-0) needed a franchise-record 21-point comeback to win their opener at San Diego 31-28.
On Sunday, they charged back from an eight-point, fourth-quarter deficit against the Titans (1-1).
"It's just great character for us to find a way to win two weeks in a row like that," Kubiak said.
Arian Foster's 1-yard touchdown and 2-point conversion tied it at 24-24 with less than two minutes left.
Houston forced a punt and got within field goal range after that. But Randy Bullock's 46-yard field goal attempt bounced off the left upright to force overtime. It was his third miss of the day.
The Titans were disappointed they let this one get away.
"We've got to close games out," Tennessee safety Bernard Pollard said. "We have to be more disciplined for a full 60 minutes."
Hopkins, a first-round pick, finished with seven receptions for 117 yards. Schaub threw for 298 yards with three touchdowns and two interceptions.
Houston's Brian Cushing had 11 tackles and two sacks and J.J. Watt added a pair of sacks.
Johnson got the Texans to the 2-yard line with a 21-yard catch to set up Foster's score. The play was first ruled an incomplete pass, but Kubiak challenged and the call was overturned.
Johnson was shaken up on the play after a hit by Pollard and did not return.
The Titans took a one-point lead with a 10-yard touchdown grab by Delanie Walker, and extended their advantage to 24-16 when Alterraun Verner returned an interception 23 yards for a touchdown on Houston's next drive.
A poor offensive series by the Titans ended with a safety by Houston to push the lead to 16-10 early in the fourth quarter.
The Titans had penalties for a personal foul, holding and delay of game to back them up to their 2.
On the next play, Chris Johnson carried to ball and it was spotted just outside the end zone. But Kubiak challenged the call and the ruling was reversed to give the Texans a safety. It was the second one for Tennessee in as many weeks.
Houston took the lead when Owen Daniels stretched out to grab a 12-yard touchdown reception near the back of the end zone to make it 14-10 in the third quarter.
The Texans got a boost on that drive when Schaub completed an 11-yard pass to Hopkins and was knocked in the helmet by Ropati Pitoitua to add a 15-yard roughing the passer penalty onto the play.
Then the Texans' defense went to work. Watt sacked Locker on first down for a 7-yard loss and the Titans soon had to punt.
The Texans wasted no time getting going, scoring on their fifth play of the game when Schaub found Garrett Graham on a 1-yard pass. A career-long 60-yard run by Ben Tate got Houston to the 6-yard line.
Tate got a couple of extra yards out of the nifty run when he stiff-armed a defender a darted away.
But that drive was one of the few offensive bright spots on Sunday until overtime.
Tennessee tied it when Locker connected with Kendall Wright on a 6-yard touchdown. The Titans received an unsportsmanlike conduct penalty for the choreographed dance that Wright, Johnson and Britt did after the score.
Houston's offense struggled on Sunday after its opening drive, and Bullock missed 50-yard field goals in the first and second quarters.
Pollard intercepted Schaub near the end of the first half, and Rob Bironas -- who had missed from 48 earlier in the second quarter -- made a 47-yard try to put Tennessee up 10-7 at halftime.
Cushing's two sacks were a career high. ... The Titans sacked Schaub twice. ... Andre Johnson finished with 76 yards receiving.