"We enjoyed it," Donovan said. "This is our first game. We are happy for us, but we're mad for the loss."
Donovan got the nod at second base, with Dee Gordon being given his first off-day of the season. Jhonatan made his first start at catcher, getting the call with J.T. Realmuto being given the day off.
The brothers have been teammates in the past playing winter ball. They were together in Spring Training with Miami, but not on the field at the same time.
"It's a dream playing with my brother, but we lost the game, and that was ultimately [what mattered]," Jhonatan said.
The brothers faced each other in 2012, when Donovan was with Miami and Jhonatan was with the Nationals. Their parents traveled from Colombia for that game.
Jhonatan was a non-roster invitee, and he opened the season at Triple-A New Orleans. The RBI double was his first hit with the Marlins, and it put Miami in front, 2-1, after the Phillies had tied it in the top of the fifth.
Donovan, who has seen regular playing time the past few seasons at second base, did commit two errors on Sunday.
Manager Mike Redmond, a backup catcher in his big league career, noted how tough it is to be sharp when used sparingly.
"It's tough to keep a rhythm when you don't get to play," Redmond said. "I've been there."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro. This story was not subject to the approval of Major League Baseball or its clubs.