BOSTON -- David Ortiz's final home opener as an active player at Fenway Park became an unforgettable event for the slugger before the game even started.
In a development that was a surprise even to Ortiz, his 15-year-old daughter, Alex, was invited on to the field and belted out a stirring rendition of the national anthem before the Orioles' 9-7 victory.
Ortiz covered his face for part of the performance, seemingly caught up in the emotion of the moment.
"It was a surprise, a beautiful surprise," Ortiz said. "At some point, you start thinking about your kids and the way you raise your kids and everything that you've been through. I got caught into those memories, and it was beautiful."
As Alex finished singing, her father came over for a hug and a message.
"He said to me, 'Don't ever surprise me like that again,"' Alex Ortiz later told the media.
How did Alex and the Red Sox pull off such a spontaneous moment?
"I didn't actually think it would work, but we found a way to do it," said Alex Ortiz. "We had Carolina [Martinez], Pedro's wife, come down so it looked like we were just watching [the ceremony]. It worked."
Alex didn't see any tears from her father, but she heard there might have been some.
"I wanted him to be emotional." said Alex Ortiz. "Somebody told me that he cried and I was like, 'Yes.'"
The author of countless clutch hits throughout his career, Ortiz said he was more relaxed entering any of those at-bats than he was watching his daughter sing in front of a crowd of 37,160 at Fenway.
"I was nervous," said David Ortiz. "I was dying. It wasn't even about me. It was about her. Whoever has kids knows how that goes when you're watching your kid perform in anything. That was like my first big moment watching one of my children just doing something pretty big. Now I understand my dad and my mom and my family when they used to watch me, they all used to be very nervous. Now I get it. It was unbelievable. Hopefully it stays in everybody's memory."
The performance included a lot of prep work -- all of which took place while Ortiz was out of town for Spring Training and the first road trip of the season.
"I owe actually doing it to my chorus teacher," said Alex Ortiz. "She motivated me to do it. She asked me if I wanted to do it and she got in touch with Dan Lyons and then they had me do it. So I would practice at the school and I would practice with her at home, but he was doing Spring Training so it worked out."
At the start of the ceremony, a montage of Ortiz's career highlights played on the scoreboard with the John Lennon classic "Imagine" playing over the video.
Joining Ortiz in a collective first pitch were fellow Boston sports icons Bill Russell (Celtics) and Bobby Orr (Bruins). Ty Law, who won three Super Bowls with the Patriots, rounded out the impressive quartet.
The Red Sox then called three of Ortiz's favorite former teammates on to the field -- Pedro Martinez, Jason Varitek and Tim Wakefield. The four men chanted "Play Ball" into the microphone, and the game started a few minutes later.
Ortiz announced back on Nov. 18 -- his 40th birthday -- that this would be his final Major League season.
The slugger went 2-for-5 with an RBI in his final home opener.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.