Zimmerman hit a go-ahead, two-run homer off Danys Baez in the eighth inning and the Washington Nationals rallied for a 7-5 win over the Philadelphia Phillies on Thursday.
Adam Dunn also connected for the Nationals, who stopped Philadelphia's five-game winning streak.
Chase Utley hit his fourth homer in three games and Shane Victorino also went deep for the Phillies.
Trailing 4-2 in the eighth, the Nationals scored three off Baez (0-1) to take the lead.
Dunn led off with a deep drive to right. After a one-out walk to Ivan Rodriguez, Zimmerman lined an opposite-field shot to right for his first career homer as a pinch hitter. The All-Star third baseman wasn't in the starting lineup for the fourth straight game because of a left hamstring injury.
"I think I got around the bases a little better than he did," Zimmerman joked when asked if he felt like Gibson. "I can run around a little bit."
In Game 1 of the 1988 World Series, a gimpy Gibson stepped in with two outs in the bottom of the ninth and connected for a pinch-hit, game-ending homer against Oakland's Dennis Eckersley in a 5-4 Dodgers win. Gibson, who didn't start because of a strained left knee, limped around the bases in one of the most dramatic finishes in series history.
"It was just good to get in the game and be a part of it," Zimmerman said. "It's never fun to just sit and not be able to help. To help win a game here is a great feeling."
On Jackie Robinson Day in the majors - all players wore No. 42 - the Phillies received their 2009 NL championship rings before the game. Philadelphia fell two wins short of repeating as World Series champs last year, losing to the New York Yankees.
The Phillies are trying to become the first NL team in 66 years to win three straight pennants. They're off to a 7-2 start.
Tyler Clippard (2-0) pitched 1 1-3 innings of scoreless relief to earn the win. Matt Capps got the last five outs for his fourth save in four tries, and his first ever longer than one inning. He allowed a solo homer to Victorino in the ninth.
Rodriguez hit a two-run single off Ryan Madson in the ninth to give the Nationals a three-run cushion.
Called up from Triple-A to replace Garrett Mock in Washington's rotation, Scott Olsen allowed four runs and five hits in 5 2-3 innings.
Phillies starter J.A. Happ allowed one unearned run and three hits in 5 1-3 innings. The left-hander had to pitch out of trouble often because he walked six, tying a career high.
"I need to be more consistent," Happ said.
Olsen pitched well until the sixth. Two-out walks to Jayson Werth and Raul Ibanez loaded the bases. Juan Castro then singled to right for a 3-1 lead. A frustrated Olsen slammed his glove and cap in the dugout after being pulled.
"Olsen did a very good job against a hot ballclub," Nationals manager Jim Riggleman said.
Clippard walked pinch-hitter Greg Dobbs with the bases loaded to force in Philadelphia's fourth run.
First baseman Ryan Howard's throwing error after Nyjer Morgan was picked off in the third helped Washington tie it at 1. Morgan scored on Cristian Guzman's groundout.
Philadelphia's bullpen hadn't allowed a homer in 29 1-3 innings until Dunn hit hits first of the year off Baez.
"I left a couple pitches up in the strike zone and they made good contact," Baez said. "You have to keep the ball down no matter where you play. It's not the ballpark."
The Phillies received 14-carat white gold rings featuring two rubies on either side to signify the consecutive championships. The top of the ring looks like a baseball diamond, with the basepaths done in rubies and the bases in diamonds.
NOTES: Roy Halladay will pitch on regular rest against the Marlins on Friday, pushing Jamie Moyer's start back to Saturday. It'll be Halladay's home debut with the Phillies. ... A crowd of 44,157 was the 45th straight sellout at Citizens Bank Park. ... The Nationals return home for the next 10 games. ... Happ, who was 12-4 as a rookie last season, hasn't allowed an earned run in 10 1-3 innings.
