And his mother, Linda O'Keeffe, said her favorite part was watching him hit that pitch in the same outfield that her son has dreamt of playing in for as long as she can remember.
"It was just so amazing," she said. "For him to be able to get down here and play baseball is such a blessing for him and such an experience that we know he would never have otherwise."
Daniel O'Keeffe has Down syndrome, has endured two open-heart surgeries and on Friday joined a group of other special needs children for an inning-long baseball game in front of family, friends and fans in left field at Chase Field for the fourth annual Challenger-Champions game.
"It's a big thrill to play on a Major League diamond for anybody," Major League Baseball vice president of community affairs Tom Brasuell said. "Some of these kids never thought they would get a chance to play at all and we're trying to treat them like Major Leaguers."
The game featured a group of local Little League All-Stars against PONY League All-Stars from around the Phoenix area.
"I had a lot of fun out here today," 21-year-old Devin Fetterhoff said, noting that he wished the game was held in right field so he could have been closer to where D-backs All-Star right-fielder Justin Upton plays.
But for as much fun as the participants had, the parents watching might have had just as much fun.
"I can't tell you how exciting it was," Linda O'Keeffe said. "It's just so great for them to put this on."
Her son Daniel has been playing baseball since the age of 8 and has to wear a black heart protector over his chest when on the field.
Daniel said baseball is his favorite sport, the D-backs his favorite team and, like, Fetterhoff, Upton is his favorite player.
"I loved it," Daniel said of the experience.
Umpiring the game was Extreme Makeover designer Paul DiMeo and on the field was former D-backs infielder Jay Bell.
"It was extremely special," Bell said. "These are a bunch of kids that, yeah, they're special needs children, but they love the game as much as anyone else.
"Today was a lot of fun and I really enjoyed being part of the event. tt was just great to see the kids enjoy the game."
Anthony Fenech is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.