The Washington Nationals vie for a franchise-high 11th consecutive victory when they host the San Francisco Giants in the opener of their three-game series. Washington posted its fifth walk-off win in six contests Thursday as Denard Span scored on an error in the ninth inning for a 1-0 victory over Arizona. The Nationals also captured 10 in a row in 2005 while the Montreal Expos accomplished the feat three times.Washington, which owns a seven-game lead over second-place Atlanta in the National League East, is 7-0 on its 10-game homestand following the four-game sweep of the Diamondbacks. San Francisco defeated the Chicago Cubs 5-3 on Thursday for its fourth win in five contests. Buster Posey went 4-for-4 with a solo homer and Pablo Sandoval collected three hits and two RBIs for the Giants, who are one game ahead of Atlanta for the second wild-card spot and 3 1/2 behind the first-place Los Angeles Dodgers in the NL West.TV: 7:05 p.m. ET, MLB Network, CSN Bay Area (San Francisco), MASN (Washington)PITCHING MATCHUP: Giants RH Tim Hudson (8-9, 3.03 ERA) vs. Nationals RH Doug Fister (12-3, 2.20)Hudson's winless streak reached five starts Saturday as he escaped with a no-decision against Philadelphia after surrendering five runs on eight hits and three walks in four innings. The 39-year-old has registered just one victory in his last 11 outings but has yielded three runs or fewer seven times in that span. Hudson improved to 17-5 with a 2.37 ERA in 30 career starts versus the Nationals franchise June 12, when he allowed just an unearned run over seven frames.Fister is coming off his third consecutive start in which he did not allow an earned run, but he was forced to settle for a no-decision against Pittsburgh on Sunday after yielding two unearned runs and five hits over seven innings. The 30-year-old has held opponents to three runs or fewer in each of his last 10 outings, going 7-1 in that span. Fister won his first career meeting with the Giants on June 10, scattering eight hits over seven scoreless frames at San Francisco.WALK-OFFS1. Washington's 10-game winning streak matches Kansas City's run earlier this season for the longest in the major leagues in 2014. Seven of the Nationals' victories have been one-run decisions.2. San Francisco has gone a season-high nine straight contests without an error.3. The Nationals are the first team with five walk-off wins in six games since the 1986 Houston Astros.PREDICTION: Nationals 5, Giants 3