"I wasn't trying to go deep," said Martin, after hitting his first career grand slam. "Chacon was throwing his sinker low in the zone, but the one I got was up."
Martin sent the crowd of 48,995 at Chavez Ravine into a frenzy when he drilled the 2-2 offering from Chacon into the Dodgers' bullpen. The homer capped off a stunning comeback by the Dodgers, who, once again received great pitching from their bullpen.
"We're doing what we expect to do," said reliever Joe Beimel, who was one of four relievers to pitch one inning in the victory. "Our job is to keep the game close so our hitters can do what they did tonight."
The Dodgers got four innings of shutout baseball from pitchers Chin-hui Tsao, Beimel, Takashi Saito and Jonathon Broxton (1-0), who picked up his first win of the season.
Starter Brad Penny came into the game looking to win his fourth consecutive game and become the first Dodgers pitcher to win his first four games of the season since Kaz Ishii did it in 2002.
However, Penny struggled with his command, walking three batters in the third inning, allowing three runs in six innings of work. Penny also seemed to get frustrated when a few questionable pitches were called balls by home-plate umpire Joe West.
"You guys saw the call," Penny said. "The guy missed some calls, especially the 2-1 pitch to [Adam] LaRoche."
After Penny walked LaRoche with the bases loaded in the third, manager Grady Little came out to support his pitcher and was thrown out of the game for arguing balls and strikes.
"You can't argue balls and strikes, that's why I got tossed," Little said. "I was just happy that Brad kept his composure."
The Pirates scored first, capitalizing on an early error by Martin in the first inning. Chris Duffy led off the game with a single and advanced to third when Martin's throw to second hit him as he was attempting to steal. Duffy later scored on a ground ball by Jack Wilson.
The Dodgers came right back to tie the game in the bottom half of the first. Nomar Garciaparra hit a blooper to right field that dropped in front of a sliding Xavier Nady for a two-out double. Jeff Kent, who is second on the team in RBIs behind Garciaparra, then promptly lined a ball into left, scoring Garciaparra.
The third inning started innocently enough for Penny, who walked Pirates' pitcher Ian Snell and then got Duffy to fly out to Luis Gonzalez in left. Wilson followed with a single, putting runners on first and second.
Second baseman Freddy Sanchez grounded out to first, moving the runners to second and third. Penny followed by walking the next two batters and throwing a wild pitch, allowing Snell and Wilson to score.
The Dodgers made it a game by scoring a run in the sixth to make it 3-2, setting up an eventful ninth inning.
Pinch-hitter Wilson Valdez sparked the Dodgers in the ninth reaching base on a fielder's choice, then going to third on a wild pitch and taking third on an overthrow by catcher Ronny Paulino.
"I just wanted to be aggressive out there," Valdez said.
Valdez stayed aggressive on the basepaths, scoring four pitches later on a passed ball. Pirates closer Salomon Torres covered the plate on the play and almost tagged out the speedy infielder.
"When I saw the ball bounce away from the catcher, and the pitcher didn't move to cover home I knew I could make it," Valdez said. "He tried to block the plate, but I slid to the side."
With the score even at 3, the Dodgers got another solid inning of relief, this time by Broxton, who shut down the Pirates in the top of the 10th, setting the stage for Martin.
Juan Pierre led off the inning with a line drive to right field and moved to second on a single by Kent. Gonzalez saw five pitches from lefty Damaso Marte before being walked, setting the stage for Martin.
With the count 2-1 to Martin, Chacon, who replaced Marte, threw a sinker low and inside for a called strike. Martin stepped out of the batter's box and shook his head, upset with the call. The next pitch, well, that was the Wow!
"I thought that pitch was a little low," Martin said. "But that next one was all mine."
Jayson Addcox is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.