Nationals 9, Giants 2: Ian Desmond went 3-for-5 with a career-high five RBIs and Stephen Strasburg yielded one run over six innings as visiting Washington routed San Francisco in the opener of their four-game series.

Denard Span also was 3-for-5 with two runs scored and Jayson Werth added two hits and two RBIs for the Nationals, who snapped the Giants’ five-game winning streak. Strasburg (6-4) cruised to his third consecutive victory by allowing just four hits while striking out seven.

Washington recorded four extra-base hits in the first three innings against Ryan Vogelsong (4-3) and led 4-1 after Desmond delivered a two-out, two-run single in the third. Vogelsong allowed a season-high six runs on nine hits over six frames and saw his ERA climb to 8.83 in four career starts against the Nationals.

Vogelsong retired eight in row before exiting after Span doubled to begin the seventh, and Kevin Frandsen followed with a single. The Nationals broke open the game with five runs on five hits in the inning, a rally capped by Desmond’s two-run double off George Kontos.

Wilson Ramos had two hits, scored twice and drove in a run for Washington, which collected 12 hits and won for the eighth time in their last 10 games. The Nationals’ starting pitchers have a 1.23 ERA, 51 strikeouts and one walk over the last seven contests.

GAME NOTEBOOK: SS Brandon Crawford and 1B Joaquin Arias had RBI singles for the Giants, who lost for the fourth time in 14 games against National League East opponents this season. ... Giants CF Angel Pagan was held out of the starting lineup for the second consecutive game with a bruised right shin, but he grounded out as a pinch hitter to begin the ninth. … Washington 3B Anthony Rendon missed his third straight contest with a swollen right hand and is listed as day-to-day.