United’s Dwayne De Rosario, foreground, and Khari Stephenson of San Jose go for the ball during the Earthquakes, 5-3 victory in Santa Clara, Calif. Missing three injured defenders, D.C. yielded three goals for the first time since 2008. (Ezra Shaw/Getty Images)

After a promising start, D.C. United conceded three goals in a 12-minute stretch of the first half Wednesday night and watched its seven-game unbeaten streak crumble with a 5-3 loss to the San Jose Earthquakes in Santa Clara, Calif.

With three center backs out with injuries, United (4-3-3) failed to muster a resistance against the Western Conference leaders (7-1-1), who are on a 6-0-1 run.

San Jose’s Chris Wondolowski claimed the MLS scoring lead (10) with a pair of goals and Steven Lenhart added two.

United, coming off consecutive victories in league play for the first time in almost three years, had not yielded five goals since September 2008 at Los Angeles.

Defenders Emiliano Dudar (hamstring), Dejan Jakovic (ankle) and Ethan White (knee) weren’t available, prompting Coach Ben Olsen to move midfielder Perry Kitchen onto the back line.

United went ahead in the eighth minute on a magnificent strike by Dwayne De Rosario. Surging on the right, Danny Cruz cut back and lost possession. The ball rolled into the path of De Rosario, who one-timed a swerving 26-yarder into the top right corner for his second goal of the season.

However, San Jose’s consistent pressure resulted in goals by Lenhart in the 19th minute, Wondolowski in the 21st and Justin Morrow 10 minutes later.

Lenhart scored on a 20-yard one-timer. Wondolowski finished deep in the box after collecting Simon Dawkins’s touch. After United’s sloppiness resulted in a corner kick, Morrow sent a half-volley on target. Diving to his left, goalkeeper Joe Willis appeared in position for the save, but Cruz’s instinctive effort to clear it lifted the ball over Willis.

San Jose’s Jon Busch made a sensational save on De Rosario’s bicycle kick in the 35th minute.

United cut the deficit to 3-2 in the 64th minute when Andy Najar crossed to Daniel Woolard for a diving header, but Wondolowski (header) and Lenhart (rebound) answered five minutes apart. Hamid Salihi scored his first goal for United in the 88th minute — the second straight three-goal performance by D.C.

United will play at Toronto FC (0-7-0) on Saturday afternoon.