He has become a clutch one.
Lose your top receiver? No worries. Instead of hanging his head, Flacco looked downfield to hit Yamon Figurs for a 43-yard touchdown.
Lose the momentum of the game in the second half? No problem, either. Flacco nonchalantly capped a nine-play, 78-yard drive with a 1-yard touchdown pass to Todd Heap in the fourth quarter.
"He's calm under fire," wide receiver Derrick Mason said of Flacco. "I know that's a cliche. But when things aren't going well, he stays calm no matter what the situation is."
Flacco's statistics suggest he had a solid but not spectacular game. He completed 15 of 23 passes for two touchdowns and no interceptions.
But it's when he produced that underscored his role in the Ravens' highest-scoring day in three seasons.
The offense let out a collective gasp when Flacco's overthrown pass led to Mason's dislocating his left shoulder midway through the first quarter of a scoreless game.
Then, two plays after his favorite target went to the sideline, Flacco slung a deep pass to Figurs down the middle of the field to put the Ravens ahead 7-0.
Flacco said he didn't think Figurs would be open because the Texans showed a cover-2 defense (both safeties playing deep). But one safety bit on Mark Clayton's route, leaving the speedy Figurs one-on-one with cornerback Jacques Reeves.
"The way they played it, he ended up popping open," said Flacco, who has thrown a touchdown of at least 40 yards in three straight games. "I wasn't really quite sure whether to believe it or not."
It was the first touchdown catch - and only the second career reception - for Figurs, Mason's replacement, who wasn't surprised Flacco spotted him getting behind his man.
"He always tells me to be ready to get the ball no matter what the play is," Figurs said.
The most telling part of Flacco's game recently has been his play in the second half.
A week ago in Cleveland, Flacco led the Ravens' comeback after the Browns had scored touchdowns on consecutive possessions to open the third quarter.
He faced another momentum swing at Reliant Stadium. One play after Matt Stover missed a 50-yard field-goal attempt, Texans receiver Kevin Walter scored on a 60-yard pass to cut the Ravens' lead to 19-13 with 3:01 left in the third quarter.
On the next series, Flacco answered with a drive jump-started by his 8-yard scramble and a 21-yard pass to Mason (who returned in the second half).
The Ravens were also helped by three Houston penalties - the last was pass interference that gave the Ravens first-and-goal at the Texans' 1-yard line.
Flacco then found Heap for a 1-yard touchdown to put the Ravens ahead 27-13. Flacco's first touchdown connection with Heap ignited a 22-point fourth quarter that gave the Ravens their largest margin of victory on the road since they routed Cleveland, 35-0, in December 2003.
"They were starting to feel they are going to get back in the game," Flacco said. "So, we just knew we needed to go back down there and do what we've been doing all game - keep moving the ball and keep getting first downs. And when we get down there, we got to capitalize on our chance to get the ball in the end zone."
The Ravens capitalized on a play that was far from perfect.
Going in motion to his left, Heap acted as if he were blocking before trying to sneak out to the left flat for the pass. But he got tripped up by a Ravens lineman and started to stumble.
Heap braced himself in time and was able to run uncovered, where a backpedaling Flacco threw a short touch pass to him.
"He was only guy on the route," Flacco said. "I saw him kind of stumble down, and I was like, 'Oh no.' I started backing up and backing up. I trusted that he would come up. He was wide open. So, it was pretty easy."
Flacco has made quarterbacking look easy during the Ravens' winning streak. In his past four games, he has six touchdown passes and no interceptions.
More importantly, Flacco has played his best when the Ravens have needed him the most.
"He doesn't get flustered," Ravens coach John Harbaugh said. "Momentum swings don't affect him too much. He comes out and plays the next series and takes care of business. That's the kind of person he is. He played well when he had to, no question about it."