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. 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.