The Steelers defense forced three Kyle Orton interceptions and Clark's replacement at free safety, Tyrone Carter, got two of them. Carter returned one of his picks 48 yards for a second-quarter touchdown, and Pittsburgh dominated the suddenly vulnerable Broncos, 28-10, at Invesco Field at Mile High.
Tomlin, whose team improved to 6-2, made the call to keep Clark in street clothes, mindful of the defensive back's previous medical emergency in the altitude in Denver two years ago. Clark has a rare form of sickle-cell trait that is aggravated by altitude.
His ailment caused complications during an Oct. 27, 2007, game in Denver and Clark nearly died -- he had his spleen and gall bladder removed in separate operations and lost 30 pounds. Although Clark was medically cleared to play Monday night, teammates urged the safety to forgo this game and Tomlin -- who was deeply concerned for the player's health -- held him out.
"Some things are more important than football ... He's probably still hacked at me," Tomlin said with a laugh. "He understood where I was coming from. But it doesn't make it any easier. He's a competitor. He wants to play."
Carter, who has started five games this season -- four as an a injury replacement for Troy Polamalu -- said he was playing for his buddy, Clark, all the way. And the large contingent of Terrible Towel-waving Steelers fans who dotted the crowd of 76,716 at Invesco loved every bit of it.
"Ryan is like a brother to me, man," said Carter, a 10th-year veteran who got a hug from Clark on the sideline after his touchdown return. "We've been in this thing together for a long time. When he first got here, I welcomed him with open arms, just like he was my brother. The relationship we have now, the bond is so tight between all of us.
"To know that he couldn't play today and to know that he wanted to be out there [because] of the nature of his illness, I just wanted to make sure I went out there and played for him. Let him know, 'I'm out there for you, man.' "
Said Clark, "I might be like Wally Pipp. I better get back fast so that I don't lose my spot. He's a friend and a teammate, and he did an awesome job tonight. I'm proud of him."
The Steelers' sixth-ranked defense, which was No. 1 in the NFL against the run, shut down any hopes that the 6-2 Broncos had of going to the ground with Correll Buckhalter and Knowshon Moreno. Denver -- which has now dropped consecutive games, losing 30-7 to Baltimore in Week 8 -- was held to 27 rushing yards, and the two backs averaged just 1.9 yards per carry.
But it was the swarming Pittsburgh secondary, led by Carter's two picks and Polamalu's fourth-quarter interception at the Denver 25-yard line -- a turnover the Steelers quickly converted into a 25-yard Ben Roethlisberger touchdown pass to rookie flanker Mike Wallace -- that decided this pivotal AFC battle. Roethlisberger completed 21 of 29 passes for 233 yards and three touchdowns, although he had a second-quarter sack and fumble converted into a 54-yard touchdown return by Broncos rookie linebacker Robert Ayers.
Orton, who had thrown only one interception before Monday night's meltdown, has been forced to throw more as opponents clamp down on the Broncos' ground attack. And that has led to the kinds of mistakes he once made with the Chicago Bears.
"We went back to the film when he was with Chicago, and he threw a lot of picks there," said Clark, who found out midweek that he would get the start for Clark. "We saw that guys had opportunities earlier this season to make picks but they dropped them.
"He always keeps his eyes on his target -- he doesn't fake you out too much like Brett Favre or Tom Brady or some of the other veteran [quarterbacks]. He'll lock in on his receivers a lot."
Orton completed 23 of 38 passes for 221 yards. He said his back-to-back struggles against the Ravens and Steelers proved that the once 6-0 Broncos can't afford to have these breakdowns if they hope to hold off the surging San Diego Chargers in the AFC West. The top teams in the division clash on Nov. 22 in Denver.
"They [Pittsburgh and Baltimore] are two good defenses, and certainly when you play those guys, the margin for error is very small," Orton said. "You have to get all 11 guys on the same page and execute for 10, 11 plays in a row. We haven't been able to do that for one reason or another, and we have to get it back on track. As a quarterback, I put it on myself.
"It is my offense, and I will get it back on track."