San Francisco scored four runs in a single inning and Todd Wellemeyer rose went six solid innings as the host Giants defeated the Washington Nationals 4-2 on Tuesday night.

The victory ended the Giants’ season-worst five-game losing skid.

San Francisco scored just one run during Oakland’s three-game sweep over the weekend. Their slumbering offense erupted in the fifth inning by scoring four times after two were out.

Wellemeyer singled off Livan Hernandez (4-3) and moved to second on Andres Torres’ single. Edgar Renteria then singled in one run before Freddy Sanchez doubled in two. Pablo Sandoval followed by doubling home Sanchez.

Wellemeyer (3-4) nearly lost his spot in the rotation but pitched well tonight giving up just two runs and four hits over six-plus innings.

Wellemeyer had given up just one hit entering the seventh but Ryan Zimmerman, Adam Dunn and Josh Willingham all singled to drive him out of the game. Zimmerman scored on Willingham’s hit and Dunn scored later in the inning on a sacrifice fly.

Brian Wilson struck out the side in the ninth for his 11th save of the season.

Hernandez gave up four runs and seven hits in five innings.