In rallying to beat Baltimore 13-9 last Sunday to win the AFC North, Roethlisberger didn't lead a touchdown drive until putting together a 92-yard drive during the closing four minutes that ended with his 4-yard TD pass to Santonio Holmes.
"Our quarterback lives by those moments," coach Mike Tomlin said. "Some people relish those moments. Other people don't. He's one that does."
Similarly, the Steelers didn't score a touchdown until the offense and defense each got into the end zone during the final 2:04 of their 20-13 decision over Dallas two weeks ago.
The Steelers may need another such finish to win Sunday at Tennessee (12-2) in a game that may decide home field advantage throughout the AFC playoffs.
Remarkably, a Steelers offense that is close to being in the bottom fourth in the league in yardage and the bottom third in scoring has outscored their opponents 55-3 in the final three minutes of games since a season-opening 38-17 win over Houston.
Another example of being good when they need to be: The Steelers have a 37-0 scoring advantage in the fourth quarter of their last three games after scoring 29 points in the first three quarters.
Being so dominant during the key stretch of many games has allowed the Steelers to pull out a series of tight games by scores such as 23-20, 13-9, 11-10, 10-6, 26-21 and 20-13.
"He's a ridiculous competitor," Tomlin said of Roethlisberger. "Some people live for those moments and that's part of what makes them who they are. I truly believe he's one of those people."
Roethlisberger, who signed a contract earlier this year that pays him a guaranteed $32 million, is shouldering much of the late-game pressure due to Willie Parker's nearly season-long injury struggles. The three-time 1,000-yard rusher has only 135 yards rushing in the fourth quarter, or about one-third as many yards as he had last season.
Roethlisberger ranks a pedestrian 21st in passer rating, but acknowledges the I've-got-to-show-them aspect of his character surfaces when games are decided.
"(It's) wanting to win, I guess," Roethlisberger said.
"Desire. I wish it didn't come down to that, but sometimes it does. We'll take it. It adds to the fun and suspense. Sometimes we do it just so the fans keep watching."
It's not advisable to turn off Steelers games early, given their 6-2 record in games decided by eight points or fewer.
"There's no panic," Roethlisberger said. "The first play (in Baltimore) we went out and completed it to Hines (Ward) and I think everybody just looked at each other and said, 'We have to get it done.' It wasn't anything more than that. I didn't give any rah-rah speeches. I think the guys look at me now and know me enough to say, 'Let's just go out and do it.'"
Tomlin likes playing, and winning, so many tight games because those often are the kind played in January and February.
"I think it strengthens your team, strengthens your resolve," he said. "You have the experience of delivering and closing out football games, particularly tight ones, and playing from behind. I think we're better for the experience."
Left tackle Max Starks credits a defense that has allowed the fewest points, passing and total yards in the league for giving the offense a chance to win at the end.
"We'd like to have those nice, fantastic, flashy numbers," he said. "Pretty makes it nice and easy and comes in a gift-wrapped package. But for us, a win is a win and we've prided ourselves in our grunt work. The defense puts us in situations where we can come in the end of games, make those drives and be the hero."