PITTSBURGH — With the Pittsburgh Steelers clinging to a two-point lead in the final minutes Sunday, Ben Roethlisberger looked for the man who is rapidly becoming his favorite target.

Just four games into his professional career, that man is Chase Claypool.

Facing third-and-8 from the Philadelphia Eagles’ 35, Roethlisberger expected the Eagles to bring an all-out blitz. But when he saw them sitting back in a Cover 2 zone, he directed his receivers to new spots. The only problem? The group on the field, including Claypool and Ray-Ray McCloud, had never run that play from the spots the quarterback put them in.

“I’ve never been in that spot,” Claypool said. “That’s usually [tight end Eric] Ebron. I actually had to ask him what I was doing because I had one thing in mind and I wanted to make sure that was the right thing because it was a crucial point in the game.”

“He just told me, kind of told the whole defense, which is my fault.”

It didn’t matter.

Roethlisberger found a wide-open Claypool and connected for a 35-yard score as the Canadian rookie outran the closest two defenders to seal the Steelers’ 38-29 win and the team’s first 4-0 start since 1979.

“He’s talented,” Roethlisberger said of Claypool. “He has got some God-given abilities that not many people in this world have. He’s big, fast and strong, and he’s very, very smart. So we’re able to do those things like move him around and do some things with him. That last touchdown is a perfect example. Changed the play, and he makes it happen. I just have to give him a little bit of a cue, and it’s awesome.”

The final score was Claypool’s fourth of the day, the first time a Steelers rookie has done that. He also became the first rookie in NFL history with three receiving touchdowns and a rushing score in one game.

Claypool took to social media after the game, posting a picture of him and Roethlisberger with the message “7/11 … always open” — a nod to their uniform numbers.

7/11 … always open. pic.twitter.com/vkv49AK6vL

— Chase Claypool (@ChaseClaypool) October 11, 2020

He also had some fun with Tom Brady, who appeared to lose track of downs in the Tampa Bay Buccaneers’ loss to the Chicago Bears last Thursday.

pic.twitter.com/coMboGzRuD

— Chase Claypool (@ChaseClaypool) October 11, 2020

Claypool’s monster afternoon — which included 7 receptions, 110 receiving yards and 6 rushing yards — got started early when he ran into the end zone on a jet sweep for a 2-yard score after a seven-minute drive in the first quarter. He scored the Steelers’ next touchdown a quarter later when Roethlisberger found him for a third-down completion that turned into a 32-yard score and a 14-7 lead.

He added a third score on the Steelers’ first drive of the third quarter on a 5-yard reception coming out of a bunched four-man formation on the left side — a play they’ve run in practice each week for the past month, but with a new wrinkle Sunday.

“Every single time I’ve thrown it to Ebron to the other side,” Roethlisberger said. “Today they kind of had two guys over there, so I threw it to Chase. We have had that in in practice, and we practice it at least once a week, but I’ve never thrown it to Chase yet.”

As the game progressed, Roethlisberger’s trust in the rookie out of Notre Dame was obvious. He looked for him on third downs and gave him a chance to make tough catches. One would-be touchdown got called back when the officials whistled Claypool for offensive pass interference on a sideline reception, and another catch got wiped out when replay determined he got only one foot down on the sideline.

“You’ve got to make those plays,” Claypool said of his third-down conversions. “He’s trusting you. He puts a ball right where it needs to be and he’s trusting you to make those plays. You make those plays and the trust builds faster than it would.”

The fact that Roethlisberger targeted Claypool 11 times — nearly double the next-most-targeted player (Ebron, six) — shows the fast rapport the veteran quarterback has built with the rookie, whom he and coach Mike Tomlin consistently praised during training camp.

Claypool had a limited role in his first two games as a Steeler, but he was efficient with his touches. He caught all five targets in the first two weeks — including an 84-yard catch-and-run against the Denver Broncos in Week 2. In Week 3, Claypool’s snaps increased dramatically after wide receiver Diontae Johnson left with a concussion. Claypool wound up playing 76 percent of snaps in his absence.

A similar thing happened for Claypool against the Eagles on Sunday when Johnson went down with a back injury on a punt return early. Claypool absorbed his snaps and more than made the most of them.

His breakout performance puts him in the conversation with other Steelers such as Antonio Brown and Le’Veon Bell, who are the only other Steelers players with at least three touchdowns and 100 scrimmage yards in a single game.

But even after such a dynamic and game-changing performance from his rookie, coach Mike Tomlin downplayed Claypool’s day.

“A lot of it may not have to do with him and his skill set,” Tomlin said. “We just have a well-balanced attack. We have guys the people have to account for, guys like JuJu [Smith-Schuster], guys like Diontae, and Ebron, and I just think that he’s probably a good matchup for whoever people have assigned up [on] him from a man-to-man standpoint … and that’s the strength of having a deep group of guys that are capable of making plays. Week in and week out there are going to be different guys that step up and ascend based off the matchups that are presented, and he had a good matchup this week.”

Claypool said he appreciated Tomlin keeping his ego in check.

“He definitely kept telling me to stay humble,” he said. “That’s something I always do in my life. He doesn’t have to worry about that. I do appreciate him keeping me grounded because in times like this, you can definitely lose sight of important things. I was staying level headed. I’m enjoying the moment, for sure, but I’m not letting it get to me.”