Hermida hit an RBI infield single in the 10th inning and the Marlins beat the Washington Nationals 3-2 Friday night for their fifth straight victory.
John Baker and Cody Ross homered for Florida (9-1). The Marlins' previous best start to a season came in 1997 and 2004, when they opened each year 8-1.
"It's great. It's always important to get off to a good start, but the thing is, it's such a long season you've got to keep it going," Dan Uggla said. "This start's not going to be worth (anything) if we don't keep it going."
Jorge Cantu got the winning rally started with a two-out single off Saul Rivera (0-2) and moved to third on Uggla's bloop hit to right. Hermida hit a grounder deep in the hole at shortstop, and Alberto Gonzalez's only play was a late throw to first.
Ross set the stage for Hermida's winning hit, driving a 2-2 pitch from Joel Hanrahan down the left-field line to tie it at 2 in the ninth.
"To come back in the ninth, with two outs left and you hit a home run to tie the game, it naturally gives you a spark," Hermida said. "It kind of jump-starts the team, and gives us a little momentum. Even though it's a tie game, we felt we had the momentum right there."
Leo Nunez (1-0) pitched a scoreless ninth. Matt Lindstrom worked the 10th for his second save, getting three outs after allowing a leadoff double to Elijah Dukes.
Gonzalez, filling in at shortstop with Cristian Guzman sidelined by a sore left hamstring that sent him to the 15-day disabled list after the game, had three hits and an RBI for the Nationals.
Washington has dropped eight of nine to open the season. The Nationals left 12 men on base and the game drew 19,026 for the smallest crowd in the two-year history of Nationals Park.
"We haven't been executing very well — runner on third, less than two out and runner on second, no outs," Washington manager Manny Acta said. "You have to add on when you have the opportunity."
John Lannan breezed through the first three innings but Baker connected with one out in the fourth to give the Marlins a 1-0 lead. Baker hit Lannan's first pitch into the second deck above the Nationals bullpen.
Washington scored two runs in the bottom half. Jesus Flores reached on a one-out infield single and scored on Gonzalez's double to left-center. Gonzalez advanced on Lannan's groundout, finishing a 10-pitch at-bat against Ricky Nolasco, and scored on Anderson Hernandez's single to left.
Nolasco gave up two runs and seven hits in four innings and wasn't happy about being yanked by manager Fredi Gonzalez after throwing 87 pitches.
"I thought I made my pitches when I needed to, made a couple mistakes, but what are you going to do?" Nolasco said. "Skipper's the skipper."
Fredi Gonzalez thought Nolasco had gone as far as he could with sub-par stuff.
"He was begging to go back out there," Gonzalez said. "The positive thing for me — a lesser pitcher, it's not two runs he gives up, it's five or six he gives up. His stuff wasn't quite there today like we're used to, but he still kept us in the game."
Lannan struck out eight in 6 1-3 innings. He yielded a run and three hits.