Grandal threw out a runner at the plate after an errant pitch in the top of the inning, then homered leading off the bottom half to give the NL West-leading Dodgers a 1-0 victory Sunday and extend their winning streak to four.
Arizona had runners at the corners with two outs in the 13th when J.P. Howell (1-1) bounced a pitch to Cliff Pennington that Grandal had to chase to the right of the plate. Grandal threw to Howell covering home, and the left-hander instinctively reached down behind with his glove to make a blind tag on the sliding Aaron Hill.
"We wanted to throw a backdoor slider, and he bounced it a little bit more than we would have liked to," Grandal said. "I tried to stay in front of it and keep it as close to me as I could, but it ended up hitting my arm.
Grandal said he knew the Diamondbacks would do whatever they could to score the go-ahead run.
"So the most important thing was getting to the ball as fast as I could and give him a good toss," Grandal added. "He did a good job blocking the plate. You don't really want to see a pitcher put his hand right in front of home plate. But with the game we were having, he had to do that in order for us to have a chance to win."
A giddy Howell gave most of the credit to his batterymate.
"I just dropped down and hoped for the best, and it worked out," Howell said. "It was a cool tag, or whatever, but the key thing was him getting to the ball and throwing a perfect feed to me on the run."
Moments later, Grandal drove a 1-1 pitch from Evan Marshall (0-2) into the pavilion seats in left-center for his second homer since the Dodgers acquired him from San Diego in the Matt Kemp trade.
"Knowing the momentum shift after that out, I knew they were going to come out there and try to be a hero," Marshall said. "He was just looking to elevate something, and it definitely was up. It was 95 and moving a whole lot. I certainly wanted to keep the ball down."
Marshall also surrendered a tying solo homer by Joc Pederson in the seventh inning on Saturday night before the Dodgers won 6-4.
"I thought back to last night when Joc hit a fastball against him and took him deep," Grandal said. "I know he has a good fastball and it's in the upper-90s. That's what he's comfortable throwing, so I just went up there looking for a fastball. He gave me one, and I took a good swing."
It was the Dodgers' first 1-0 win of 13 innings or longer since they beat the Diamondbacks in 14 innings on June 2, 2010, according to STATS. Their bullpen stretched its scoreless innings streak to 26.
"The key is keeping the faith," Grandal said. "After the second game of the season, there were a lot of people who said the bullpen wasn't good enough. That bothered me a lot, and it makes me mad because I take it personally. But we've got the guys that we've got in the bullpen because they're good enough to be there. Lately it's been lights-out."
Diamondbacks right-hander Chase Anderson held the two-time defending NL West champions to a pair of harmless singles through six innings and struck out seven en route to his fourth no-decision in five starts.
Los Angeles left-hander Brett Anderson, a second-round draft pick by the Diamondbacks in 2006, scattered five hits over six innings with four strikeouts and no walks.
The Dodgers' Howie Kendrick doubled to right field in the ninth and tried to take an extra base when Mark Trumbo misplayed the ball, but Kendrick was thrown out on the relay.
Dodgers: RF Yasiel Puig, on the disabled list because of a left hamstring strain, ran in the outfield and is eligible to be activated next Sunday in Colorado after a couple of minor league rehab games. ... Brandon League threw off a mound for the first time since his shoulder injury and then threw off flat ground in the outfield. ... LHP Hyun-Jin Ryu is to test his ailing shoulder on Monday in Milwaukee and will throw to hitters later in the week if there are no setbacks.
Diamondbacks: RHP Josh Collmenter (2-3) opposes Colorado LHP Tyler Matzek on Monday night in the opener of a three-game series that concludes the trip.
Dodgers: LHP Clayton Kershaw (1-2) makes his third attempt at his 100th regular-season victory when he goes against RHP Kyle Lohshe at Milwaukee on Monday night in the opener of a four-game set.