This was a special moment for Wagner, not just because he loves pitching under pressure, but because it was his first appearance in a postseason contest since 2006, when his Mets lost to the Cardinals in a heartbreaking seven-game National League Championship Series.
At the age of 38, and coming off Tommy John elbow ligament replacement surgery, Wagner had no idea how many more cracks he will get at October. So he will savor each one.
He announced his presence to this American League Division Series by striking out Chone Figgins, the Angels' dynamic leadoff man, on a 96-mph pitch. During the five-pitch at-bat, Wagner three times reached 97 mph on the radar gun.
"He's gotten so excited about being here," said Red Sox manager Terry Francona. "He wants to pitch every day. You can see him [Friday] night. He was getting after it. There's a reason he's been good for a long time. Now we're seeing it first hand. He likes to get out there. He's been fun to have around."
For Wagner, it has been extremely fun for him to be around. When he was finally finished with rehab, and ready to pitch again, he figured there would be several stints in September for a Mets' team that was not in contention.
But the Red Sox, despite an already strong bullpen, prioritized making a trade for Wagner, figuring his lightning bolt of a left arm could play a role down the stretch and into October.
In 15 regular-season games for Boston, Wagner posted a 1.98 ERA. While his velocity was down a couple of ticks, it hardly showed, as Wagner recorded 22 strikeouts in 13 2/3 innings.
And now he's savoring the chance to be pitching in the postseason, hoping the Red Sox can rally back from an 0-2 deficit in this best-of-five series.
"I was just trying to get back for the Mets and finish the year and they couldn't wait to get me back to trade me," Wagner said. "And to come to a contender, I think that's icing on the cake to have that opportunity to pitch this far into the season."
When he first came to the Major Leagues in 1996, nobody knew quite what to make of Wagner. He could hit triple digits on the radar gun, but would his diminutive physique -- Wagner is 5-foot-11 -- hold up with all that power?
Thirteen years later, that answer has come definitively, even after major surgery.
"Honestly, my biggest worry and concern every day and every game I've ever pitched is just to throw strikes," Wagner said. "Fear of failure makes you do things that you just wouldn't think you'd be able to do. Velocity has given me something from that fear of failure and that extra adrenaline. Now that I don't throw as hard, I actually have to learn how to pitch."
The numbers prove that the learning has come swiftly.
Wagner approved a trade to the Red Sox mainly so he'd have a chance to win his first World Series ring. October runs have never gone all that well for Wagner or his teams in the past.
Four times, his Astros were knocked out in the Division Series. The one that still stands out for Wagner is 1998, when Randy Johnson -- a July 31 trade acquisition at the height of his dominance -- was supposed to put Houston over the top.
"In 1998, we got Randy Johnson, but then we ran into Superman in Kevin Brown," bemoans Wagner.
Finally, in 2006, Wagner tasted the NLCS, but that didn't end the way he or the Mets had hoped.
The postseason hasn't always been kind to Wagner, as he will be the first to attest.
"I've pretty much [stunk]," Wagner said. "You can say [that]. It ain't no secret."
Wagner has pitched 12 times in October, posting a 9.28 ERA. But he did convert the precious three save opportunities he has been given in postseason, all for the 2006 Mets.
"Most of my games have been in blowouts," Wagner said. "I think I've only had a few save opportunities in six postseasons. Your numbers get skewed in certain ways, but I still [stunk]. It wasn't like I went out there and set the world on fire."
Now his job is to set up Jonathan Papelbon, a right-hander at the top of his game whom Wagner has grown to admire in their six weeks as teammates.
"Not knowing Pap until I got here and just seeing him on TV before -- not knowing who he was and just hearing what the media had to say about him -- I've been thoroughly impressed with the way he goes about his business," said Wagner. "He's one of the most intense guys I've ever seen as a closer."
Wagner knows a closer's mind-set better than anyone, with 385 career saves. There are no saves for him this October. Not with Papelbon around. But Wagner hopes to play some kind of role in saving the Red Sox's season, a task for which all hands will be on deck.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.