PHOENIX -- With another series win against a division rival, the San Francisco Giants overtook the Chicago Cubs for the NL lead with their 52 victory.
Pinch-hitter Ramiro Pena hit a tiebreaking double in the 11th inning, and the San Francisco escaped with a 5-4 victory over the Arizona Diamondbacks on Sunday to take two of three in the series.
The Diamondbacks' Jake Lamb hit a two-run home run in the eighth inning to tie it 4-4 but Enrique Burgos (0-1), Arizona's seventh pitcher, walked leadoff batter Jarrett Parker in the 11th and Pena lined the first pitch he saw into the right-field corner.
Josh Osich (1-1) pitched a scoreless 10th to get the win.Santiago Casilla escaped trouble in the 11th for his 19th save in 23 tries.
The Giants took a series from an NL West foe for the seventh straight time. The last series they lost to a team in their own division came when they were swept at home by Arizona from April 18-21.
"It's pretty big, especially for us right now when we don't have a lot of guys in our lineup," the Giants' Brandon Belt said. Just for the younger guys to step in there and step up for us big. It says a lot. It says a lot about this team."
With the outfield depleted, Belt - almost always a first baseman these days - played in left because the outfield is depleted.
"He made a nice running catch in left field," San Francisco manager Bruce Bochy said. "We were in a box today, with a couple outfielders down, three actually. That's why Brandon went out in left field and he looked comfortable."
The Giants' Gregor Blanco strained a knee in Saturday night's loss and is being evaluated. Denard Span was out with a stiff right neck.
Rookie Albert Suarez pitched six innings, and Brandon Belt and Mac Williamson each drove in a pair of runs to put San Francisco up 4-2
With one out in the eighth, first baseman Buster Posey bobbled Paul Goldschmidt's spinning grounder for an error. Goldschmidt stole second and Lamb launched Cory Gearrin's 3-2 pitch just over the fence in right field. It was Lamb's fourth homer in five games and his 19th of the season. Eleven of those home runs either tied the game or gave Arizona a lead.
Goldshmidt also homered, his 15th.
"There were opportunities in the beginning of the game and at the end there. We just couldn't get it done," Lamb said.
Yasmany Tomas led off the Arizona 11th with a single, was sacrificed to second, and a wild pitch put him on third with one out. But pinch-hitter Welington Castillo grounded out, and Peter O'Brien, another pinch hitter, struck out. O'Brien has struck out 25 times in 57 at bats since coming up from Triple-A Reno.
A night earlier, Castillo's three-run home run off Hunter Strickland in the eighth inning beat the Giants. This time, Strickland struck out Castillo in the ninth.