Dunn connects for first 3-homer game of his career, Nationals beat Padres 7-6.

Dunn hit 3 home runs, Nationals beat Padres 7-6

WASHINGTON — Adam Dunn hit three home runs in a game for the first time in his career, powering the Washington Nationals past the San Diego Padres 7-6 Wednesday night.

Dunn hit a three-run shot in the first inning, added a solo homer in the third and capped his power show with a leadoff drive in the eighth that landed in the seats above the out-of-town scoreboard in right-center field.

His last homer gave the Nationals an insurance run after the Padres had scored twice in the top of the eighth to close within 6-5. Dunn left the game in the ninth for a defensive replacement.

Dunn became the second player with a three-homer game for the Nationals. Alfonso Soriano did it in 2006. This was the first three-homer performance in the three-season history of Nationals Park.

Dunn reached the 20-homer mark for the 10th straight season. He has 336 career home runs.

Ian Desmond also hit a solo home run for the Nationals, who earned the series win against the Padres for the second time in 12 tries since moving to Washington in 2005.

Matt Stairs connected for his 20th career pinch-hit home run, tying the major league record set by Cliff Johnson.

Stairs hit a solo homer in the ninth off Nationals closer Matt Capps. The Padres put runners on the corners before Capps got Chase Headley to ground out for his 23rd save in 27 chances.

Adrian Gonzalez homered, doubled and singled twice for the Padres and drove in two runs.

J.D. Martin (1-4) got his first win since Sept. 18, 2009. He gave up two runs on six hits, walking one and striking out four in 5 2-3 innings.

Martin had gotten little run support — in his previous six starts, the Nationals scored a total of 12 runs while he was in the game — but the Washington hitters gave him an early cushion against San Diego.

Washington’s first five batters reached base, and the Nationals scored four runs before Jon Garland recorded an out.

Garland (8-6) settled down and pitched six innings, giving up six runs on eight hits, including a season-high three home runs.

The Padres rallied after falling behind 6-2 after six innings. Pinch-hitter Chris Denorfia homered in the seventh, and Nick Hundley’s RBI keyed a two-run eighth.

The Nationals’ lead was built behind Dunn.

Nyjer Morgan led off Washington’s first inning with a single and Roger Bernadina followed with a walk. Ryan Zimmerman hit an RBI single before Dunn homered to center.

Gonzalez drove in the Padres’ first two runs, with a solo home run in the first inning, his 17th of the year, and an RBI double in the third.

Dunn answered in the bottom of the third, leading off with his drive that landed just a few seats away from his first shot.

NOTES: Padres RHP Chris Young, who has been on the DL since April 7 (right shoulder strain), played catch before the game and then returned to San Diego for the expected birth of his second child. … Dunn has 26 multihomer games in his career. … The game-time temperature of 98 was the second-highest in Nationals history. Tuesday’s temperature was 99 degrees.