Freddy Sanchez’s walk-off single in the bottom of the 13th inning scored Chris Stewart and gave the San Francisco Giants a 5-4 win over the visiting Washington Nationals on Monday.

The Giants tallied their eighth walk-off win this season after Sanchez lined a two-out single down the right field line against Craig Stammen (0-1).

Javier Lopez (3-1) earned the win after pitching 1 1/3 scoreless innings.

San Francisco tied the game in the eighth with three runs on Aubrey Huff’s two-run double and Nate Schierholtz’s run-scoring single.

Before leaving after five innings in his shortest start of the season, Tim Lincecum became the eighth pitcher in the modern era with 1,000 strikeouts in his first five seasons.

Michael Morse homered in the first inning and capped the Nationals’ three-run third inning with a double off Lincecum, who allowed four runs on five hits, three walks and five strikeouts.

John Lannan gave up one run on four hits and one walk while striking out six over seven innings for Washington.