It was a record Harrison didn't mind seeing broken.
"It's great," said Harrison, who watched the game from Acrisure Stadium. "Records are meant to be broken and that was one I was happy to see go down. It's guys that played here wanting to see guys that are currently playing do better and greater things than what the previous group did and holding up what that Steelers' lore is."
Watt was grateful to have Harrison see him break the record and for his support.
"It really is special," said Watt. "I am so thankful that Deebo (Harrison) is so accepting and happy for me. He helped me when he was here, and he didn't have to. But he really took me under his wing and was able to help me grow and develop as a player as a rookie.
"And we've continued a relationship here over the last couple of years as well. And it's the Deebo way. I didn't even know he was there. And what's so cool about it is I'm sure he didn't care that anyone knew he was there. It was just one of those things that I appreciate about him. I really do."
He wasn't the only one watching. J.J. was watching as well, enjoying retirement and focusing even more on watching his 'baby' brother play.
"I love sitting down and watching him," said J.J. Watt, who is working as an analyst on CBS' NFL Today. "Even in Week 1, we have 10 screens in front of us with all of the games on at CBS. But at our individual station we have a television, and you get to choose what game is on it. Obviously, mine is on the Steelers and I get to just sit there and watch every single play. I can break down film afterwards. I really enjoy sitting down and watching him play. It's a lot of fun for me."
And when he sees him record a sack, well, his words say it all.
"It's the best," said J.J. Watt. "I love it. Because I know how hard he works, and I know how hard it is to be successful in this league, I think that is the biggest part of it. I know how incredibly impressive it is what he is doing. I don't know if everybody fully understands how impressive the things that he is doing are, and I do. I think that is why I get so excited every time he makes these plays. I am like, 'Are you kidding me, he just had three sacks in the first game of the season against one of the best teams in the league, two forced fumbles.' And everybody is like, yeah, that's T.J., he plays a great game.
"But I know every single workout, and every single practice and rep that went into that. I know how hard that is. I think that is why I have so much fun with it. Now it's a chance for me to live vicariously through him now that I am done."
Watt smiled when he heard that. Because he has been there.
"That's exactly how it was for me watching J.J. play for so many years. And it's kind of cool that the roles get flipped a little bit," said Watt. "I would always watch games and he would have these insane plays, sack fumbles and touchdowns. I would be excited, but I would always think this is normal. This is just what my brother does. Like, I didn't truly appreciate it until I got to the NFL.
"I think that's why it's so special between all of my brothers, is that we know, we've been in these locker rooms, we've been in the stadiums. We know how hard these plays are to make. So, when we make them, we respect the crap out of each other for it."
Watt knows his brother isn't the only watching closely. That is why when he gets on the field for every game, he flips a switch, going from the kid from Pewaukee, Wisconsin to NFL superstar because he wants to give it his all.
"He flips that switch all right," said Highsmith. "You don't want to mess with him when he is on the field, especially if you are the opposing team. I feel bad for tackles who have to block him.
"He brings energy. It's contagious. When he does the, 'Who ride, We ride,' before every game, it really pumps us up. I love that. If you are looking for some juice, he will definitely bring it."
There is as reason he does.
"I think that's the number one thing that people will say, especially lately about me," said Watt. "My dad always said you have to be able to flip a switch when you get out on the football field.
"I always try to carry myself a certain way off the football field, but on the field, I try to flip that switch and just let everything take over. I kind of black out sometimes. I don't know what I say, I don't know what I do. I try to have as much fun as possible. I know there's such a short amount of time that I get to play this game and I put so much work, effort and energy into this game.
"Come game day, there's moments where I'll think about all the fans that are here. One game I was looking in the crowd because I felt like I was kind of in a lull. I saw a little kid wearing No. 90, holding this sign that says this is my first Steelers game.