The 25-year-old righty kept the Cardinals in the game for 5 1/3 innings, limiting a potent Red Sox lineup to just two earned runs on two hits and three walks. He tied a career high with six strikeouts, one looking, five swinging.
"I think I did pretty good," Kelly said. "It was definitely one of the best experiences of my life, and I had a great time out there, having fun, just to get a chance to pitch in the World Series. It kind of sounds cliche, but it's definitely a childhood dream. I was just out there having a blast."
Kelly retired the first nine batters he faced, and he showed off his athleticism by barehanding an infield grounder and making the toss to first baseman Matt Adams for the second out of the game.
"That's just a reaction. It's the World Series, you want to make every play you can," Kelly said. "And usually I've had plays like that during the year where I go out and bring [the hand] back. I just decided not to bring it back and try to make a play."
Kelly was not only effective, he was efficient, exiting with a pitch count of 89 (53 strikes) in his first Fall Classic appearance.
"Just attack the zone with some fastballs, and I was just trying to go after these guys and keep my pitch count down, and mixing offspeed pitches over the plate for a strike," he said. "I wasn't trying to get too pumped up or too hyped up. I was trying to throw strikes at that point, and it seemed to be working."
After finishing the regular season with a 2.18 ERA in his last 16 outings, Kelly has been steady for the Cardinals through four postseason starts.
"We like how he works ahead in the count, and gets in the zone and works the ground balls," manager Mike Matheny said. "He had good stuff. He did a nice job today. Joe pitched a good game. And that's what we've seen -- the last two months of the season he's been very good, very consistent for us."
Chad Thornburg is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.