SAN DIEGO -- Chad Tracy has two hits in 18 days. The last one cleared the veteran's troubled mind.

The pinch hitter slammed a game-winning home run in the 10th inning to give the Washington Nationals a 6-5 victory over the San Diego Padres on Friday night.

Tracy's heroics at Petco Park negated a blown save by Nationals closer Rafael Soriano, who gave up two runs with two outs in the ninth. It made a quality start from Gio Gonzalez and a two-home-run night from first baseman Adam LaRoche stand up, and reclaim a victory that seemed so certain early on.

"That one added a few gray hairs," Nationals manager Davey Johnson said. "It seemed like we had that one sewn up neat and it got away from us there at the end. I'm happy the way it turned out and happy that Chad was able to get the job done."

Tracy has owned the Padres as a pinch hitter. His seventh career pinch-hit home run was his fifth against the Padres and his third straight.

Tracy is still hitting .162, but the home run did wonders for his mentality.

"We were all fired up, myself included," Tracy said. "As a pinch hitter going through some struggles, you stay up at night in the hotel, thinking about them until youre next at-bat. The frustration builds and builds, and finally you just have to let it all go. Typically, that's when things can turn around."

Things have certainly turned around for LaRoche.

The first baseman extended his hitting streak to 14 games with a three-run shot 431 feet to deep center in the fourth and hit his second 403 feet in the sixth inning. LaRoche's second blast followed Ryan Zimmerman's home run, which just cleared the right-field wall.

It was LaRoche's 21st multihomer game, his second this season and a sign that his early-season slump is over. LaRoche hit .189 over his first 25 games but has batted .396 during his hitting streak, which includes four home runs, two doubles and 11 RBIs.

"Adam's issues have been dispelled," Johnson said. "He had a great night tonight, but he's been on fire for a couple weeks now. It's been impressive to watch him hit like his able to."

Tracy's home run came off Padres closer Huston Street (0-3), who has allowed six home runs in 17 1/3 innings. He gave up two in 39 innings last season.

"With Huston or any pitcher, if you get a ball up in the strike zone, he has a chance to get hit," Padres manager Bud Black said. "If they square it up, it has a chance to leave the ballpark. Has it happened to Huston a few times? Yes. Am I concerned? No."

The Padres tied the game with three straight singles. Chase Headley's RBI made it 5-4 and Yonder Alonso pushed him to third with another single. Kyle Blanks evened the score with another single, which sent the game into extra innings.

It was Soriano's second blown save in 14 chances, although an error by Zimmerman made both ninth-inning runs unearned. Drew Storen got his first save of the season in the 10th.

The Nationals took advantage of Padres right-hander Burch Smith, making his second professional start. The 23-year-old gave up five runs on six hits in 5 1/3 innings. He struck out eight and walked just one, but three home runs got him in trouble.

It was still an improvement over his professional debut.

Smith gave up six runs on five hits in one-plus innings in a no-decision at Tampa Bay on May 11. He pitched a perfect first, but couldn't get an out in the second and left the game with five runs in and the bases loaded.

Gonzalez got better as the game went on, and allowed three runs -- two earned -- in 6 2/3 innings. Gonzalez walked three -- two in the first inning -- struck out five, and retired 10 straight at one point. Gonzalez hasn't exceeded two earned runs in three straight starts and six of nine this season.

"I was able to make some in-game adjustments and get back on track," Gonzalez said. "It's always good when you can do that. It's also good when things go wrong in a game and the team can rally together and still get the win."

Game notes
Washington LHP Ross Detwiler was diagnosed with an oblique strain and will miss at least one start. He was injured a start Wednesday against the Los Angeles Dodgers and had an MRI on the injury on Thursday. ... Johnson said OF Jayson Werth is still experiencing hamstring tightness and that he might not come off the 15-day disabled list when eligible on Saturday. ... The Padres placed OF Carlos Quentin on paternity leave Friday and promoted RHP Tim Stauffer from Triple-A Tucson in a corresponding move. Quentin also missed Thursday's game after the birth of his son, but he is expected back with the team on Saturday. RHP Thad Weber was designated for assignment to create room for Stauffer on the 40-man roster. ... RHP Clayton Richard, on the 15-day disabled list with a stomach virus, allowed one run in six innings of a rehab start with Triple-A Tucson. Richard is expected to make one more start before returning to the Padres rotation.