SAN FRANCISCO — Hunter Pence is healthy at last. Joe Panik has been back a few days from a concussion and is driving in runs again. The San Francisco Giants sure are starting to look like themselves again.

Oh, with that new face in the infield of Eduardo Nunez.

Panik hit a go-ahead sacrifice fly in the seventh inning, Nunez had a two-run double in his first start with San Francisco and the Giants snapped a three-game losing streak by beating the Washington Nationals 5-3 on Saturday.

Pence was activated from the disabled list after missing 48 games with a strained right hamstring that required surgery.

"It's huge, just his presence in the lineup," manager Bruce Bochy said. "He's one of our guys. In addition to the talent, he brings energy and all those intangibles. He charged up the troops being out there."

He received a roaring ovation when introduced before the game and again when he took his spot in right field before first pitch, and the outfielder acknowledged the greeting by nodding his head and saying thanks. Welcomed by another standing ovation when he stepped into the batter's box leading off the second, Pence ripped a double off the left-field wall, and the sellout crowd jumped up to cheer once more.

San Francisco hopes Pence will bring some much-needed life to a team that has won the World Series in every even year this decade — 2010, '12 and '14.

"There's no secret he's our emotional, spiritual, whatever you want to go with, leader," catcher Buster Posey said. "He's definitely a big boost."

Nunez doubled in the fourth while making his first start since joining the team in a trade from Minnesota on Thursday. He got his first at-bat Friday.

Nunez popped out foul to the catcher with the bases loaded to squander San Francisco's chance in the second. He played shortstop Saturday because Brandon Crawford, who lined into a bases-loaded triple play during Friday's 4-1 loss, had a sore left hand from a swing early in Friday's game. Crawford entered for defence in the ninth Saturday.

Santiago Casilla closed it out for his 23rd save on a day decided by the bullpens after each starter only lasted four innings.

Anthony Rendon hit a two-run homer in the third for the Nationals, who couldn't protect an early 3-0 lead hours after acquiring All-Star closer Mark Melancon from the Pittsburgh Pirates to replace the struggling Jonathan Papelbon.

San Francisco, which is beginning to get healthy, loaded the bases against former Giants reliever Yusmeiro Petit (3-2) with one out in the seventh to bring up Panik. The Giants won for only the third time in 14 games since the All-Star break.

"They were due to hit some with runners in scoring position," Nationals manager Dusty Baker said of the Giants, only 9 for 50 in such situations six games into their homestand.

Derek Law (4-1) pitched the seventh for the win.

Trevor Brown drew a bases-loaded walk from Blake Treinen in the seventh to give San Francisco an insurance run.

Rendon connected against Jake Peavy, who is winless over four outings since beating Colorado on July 4.

Reynaldo Lopez was called up from Triple-A Syracuse to make his second major league start after losing to the Dodgers in his debut July 19.

He allowed three runs and four hits, struck out four and walked five.

TRAINER'S ROOM

Nationals: 2B Daniel Murphy was held out of the lineup a day after he left the game with left leg tightness — the same side in which his hamstring has nagged him for much of this month. "Still being precautionary," Baker said, noting the training staff advised him against using Murphy. ... Baker said doctors have identified Stephen Drew's dizziness issue. "He's better as far as I know and they found what it is, so that's great," Baker said.

Giants: CF Denard Span also was out of the lineup because of a tender quadriceps from a collision at home plate Friday, but he came in to pinch hit in the sixth. Bochy wasn't sure whether he would be ready to start by Sunday's series finale. ... 3B Matt Duffy (left Achilles strain) was starting a three-game rehab assignment with Triple-A Sacramento then set to go to Double-A Richmond while the Giants are on the East Coast so he will be nearby. ... INF Ramiro Pena was designated for assignment to clear roster room for Pence's return.

UP NEXT

Nationals: LHP Gio Gonzalez (6-8) tries to win his third straight decision.

Giants: RHP Matt Cain (2-6) tries for career victory No. 100 after winning his last time out Tuesday against the Reds and hitting a three-run homer. He would become the sixth pitcher in San Francisco history to win 100 in a Giants uniform, joining Hall of Famers Juan Marichal (238) and Gaylord Perry (134), Tim Lincecum (108), Kirk Rueter (105) and Mike McCormick (104).