Wellemeyer came around to score the go-ahead run to snap San Francisco's 24-inning scoreless drought, Freddy Sanchez hit a two-run double, and the Giants ended a season-high five-game losing streak with a 4-2 win over the Washington Nationals on Tuesday night.
"That's something," teammate Aubrey Huff said of Wellemeyer's second hit of the year. "That's going to have to happen, you get something strange in baseball like a pitcher starting a rally. Sometimes you get something started in the most unlikely of places to get you out of your ruts."
Wellemeyer (3-4) allowed four hits and two runs in six innings to improve to 3-0 lifetime against the Nationals, and sparked the Giants' four-run fifth inning with that two-out single. Pablo Sandoval added an RBI double and Edgar Renteria singled in a run as San Francisco ended an 0-for-25 stretch with runners in scoring position that inning.
But Renteria tweaked his right hamstring on a sacrifice bunt in the seventh and his status was uncertain. Renteria, who just came off the disabled list Saturday from a groin injury, will have an MRI exam Wednesday.
"It's unbelievable. I don't know what to say," he said, fighting his emotions.
The Giants tagged former San Francisco pitcher Livan Hernandez (4-3) for a season-high seven hits and season-high matching four runs in five innings.
He wasn't happy to watch Wellemeyer beat him, either.
"Today I felt very good and I lose again with two outs," Hernandez said. "I lost a game in a very stupid way. Two outs, I have the game right there and I lose it."
Heavy rain threatened to wash out the game and kept the teams from taking pregame batting practice on the field, but it cleared up before game time. A strong rain began again in the top of the seventh, stopped and then briefly started again in the bottom half.
San Francisco opted not to skip Wellemeyer's turn in the rotation after Monday's off day, meaning two-time NL Cy Young Award winner Tim Lincecum will pitch Wednesday night on one extra day's rest.
Wellemeyer made his outing count.
"It was a rally starter, two outs," he said of his hit. "You've got to start somehow."
Wellemeyer allowed three straight singles to start the seventh, including Josh Willingham's RBI base hit, and manager Bruce Bochy turned to reliever Sergio Romo. Ian Desmond hit a sacrifice fly two batters later.
Brian Wilson pitched the ninth for his 11th save in 12 opportunities.
The Nationals had a tough time getting here. After completing a stretch of 20 games in 20 days, the team had planned to spend its off day Monday in the Bay Area. But the Nationals spent five hours on the tarmac Sunday night before getting sent home. Washington finally arrived in San Francisco on Monday to kick off a 10-game trip out West, but not before waiting another two hours in the plane before takeoff and an hour during a refueling stop in Kansas City.
The Giants won for the 12th time in the last 14 meetings in the series dating to the start of the 2008 season. They needed this one. San Francisco scored only one run while getting swept in three games at Oakland over the weekend.
"Who would have thought as hard a time as we were having scoring, two outs and Welley up and we score four runs?" Bochy said.
Bochy switched things up for the second straight game, and he might have to adjust again if Renteria is out.
Huff, the regular first baseman, started in left field -- his first time there since Oct. 1, 2006, with Houston -- and the first ball of the game came his way. Huff caught Nyjer Morgan's liner.
Nats right fielder Roger Bernadina went down briefly in the second after Wellemeyer hit him with a pitch on the outside of his right knee. Bernadina was checked on by trainers, then jogged it off and took first base. He was picked off moments later.
San Francisco has had only five rainouts in its current ballpark, which opened in 2000. ... Giants LHP reliever Jeremy Affeldt, who came out of Sunday's game with a left hamstring injury, had an MRI exam Monday that revealed a deep strain. He won't pitch for a few days, but planned to play some light catch Wednesday.