MIAMI (AP) -- Dramatic, final at-bat wins are becoming routine for the Florida Marlins.
It was Jacobs' first major league walk-off homer, and the second for the Marlins this week.
"Everything kind of stops for a second," Jacobs said. "It's a moment you're feeling that you're never going to forget."
"We have a flair for the dramatic these first couple of games," Florida pitcher Scott Olsen said.
It's the first time since 2003 the Marlins have had multiple walk-off homers in a season.
"It's one of those things that gets everybody excited and pumped up," Jacobs said.
Jacobs began the night with one hit in 11 at-bats (.091) through three games. He went 3-for-5 and scored three runs against Pittsburgh.
Jacobs sent Osoria's 1-1 pitch over the right-field wall.
"It was a sinker that stayed up over the plate," Osoria said.
Ryan Doumit homered for Pittsburgh, his first of the year.
Pittsburgh's Matt Morris allowed four runs -- three earned -- and eight hits with two walks and two strikeouts in five innings.
"He managed to keep us in the game for five innings and that's all we can ask," Pirates manager John Russell said.
Olsen gave up four runs and seven hits in six innings. He struck out five, walked two and faced just 13 hitters in his final four innings.
"After the first couple of innings, he didn't look right," Marlins manager Fredi Gonzalez said. "But then he settled down. The last three innings he was nails."
Four Florida relievers combined to pitch three scoreless innings. The Marlins also had two outfield assists, by left-fielder Willingham and Brett Carroll in right.
Olsen's two-out RBI single in the second and Willingham's two-run homer in the third tied the score at 3.
"I was trying to get a ball in on Willingham, who's one of their better power hitters," Morris said. "Me going in, I have to move the ball off the plate, and it caught too much of it."
Doumit homered leading off the fourth to give Pittsburgh a 4-3 lead. It was his first from the right side since homering off Cincinnati's Eric Milton on Aug. 27, 2005, and his second in 139 career right-handed at-bats.
Florida scored an unearned run in the fourth to tie the score at 4. With two outs and Jacobs on first after hitting a single, third baseman Jose Bautista and first baseman Adam LaRoche made throwing errors on the same play, allowing Jacobs to score on Willingham's grounder to third.
The Pirates announced closer Matt Capps had agreed to a $3.05 million, two-year contract that runs through 2009. ... Pirates SS Jack Wilson (strained left calf) missed the game and was listed as day-to-day. 2B Freddy Sanchez was a late scratch because of a lingering right shoulder injury. ... Florida RHP Anibal Sanchez, returning from right shoulder surgery, threw his first bullpen session before the game.