SAN FRANCISCO (AP) San Francisco answered right back after Yunel Escobar hit the game's first pitch for a home run, Ryan Vogelsong settled in to win for the first time in more than seven weeks, and the Giants beat the Washington Nationals 3-1 on Thursday night.

Matt Duffy and Buster Posey hit RBI singles in the bottom of the first against Stephen Strasburg (6-6) for the defending champions to kick off a key four-game series in a rematch of last fall's NL division series won in four games by the Giants. Strasburg, in his second start off the disabled list, suffered his first career loss to the Giants.

Vogelsong (8-8) allowed one run on three hits, struck out eight and walked four over five innings for his first victory in five starts since June 24 as San Francisco won for just the second time in seven games.

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Both teams sit in second place in their respective divisions looking to make a move over the final eight weeks.

Brandon Belt, one of the baseball's hottest hitters this month with seven home runs, added an insurance RBI single in the seventh.

Hunter Strickland relieved Vogelsong and struck out three in two perfect innings with three strikeouts. Sergio Romo struck out two in the eighth and Santiago Casilla finished for his 28th save.

Escobar sent Vogelsong's first pitch of the night over the wall in left-center for his eighth homer. It was his third leadoff clout this season, the seventh of his career and the seventh by the Nationals this year.

Washington couldn't muster any other offense after that in losing a third straight game and seventh in 11.

Nationals manager Matt Williams was delayed getting to the field for batting practice after home run king Barry Bonds paid his former teammate a visit in the clubhouse and stayed more than a half-hour.

Strasburg was handed his first career loss at AT&T Park, where he had been 2-0 with a 1.89 ERA in three previous starts. He kept alive his streak of never surrendering more than two earned runs while striking out at least seven in each of his four outings at the Giants' waterfront ballpark.

The Nationals were coming off consecutive shutouts by NL West-leading Los Angeles and arrived into the Bay Area about 2 a.m. after a night game at Dodger Stadium on Wednesday.

TRAINER'S ROOM

Nationals: 2B Dan Uggla, placed on the DL on Saturday with back spasms, will receive his World Series ring from the Giants before the series ends. He played four games for San Francisco in 2014.

Giants: LF Nori Aoki was placed on the seven-day concussion list after symptoms returned Wednesday and he had to leave the game. He was hit in the head by a pitch Sunday at Wrigley Field. ... RHP Tim Hudson will pitch two innings at Class-A San Jose to prepare himself for a potential September bullpen role. ''I've got to go out and pitch to some kids who could be my kids,'' he said. ''I can always start. If I need to be ready in 2-3 minutes, we'll see if these old bones can handle it.''

UP NEXT

Nationals: Max Scherzer (11-8, 2.44 ERA) seeks his second win in five starts following back-to-back no-decisions.

Giants: RHP Matt Cain (2-3), 0-2 over his last three starts, didn't pitch in last year's playoffs because of elbow surgery and hasn't gone more than six innings this year following more elbow issues. He is 3-2 at home against Washington with a pair of complete games.