CARSON -- Chris Wondolowski enabled the Earthquakes to exploit an advantageous situation in their quest to reach Major League Soccer's playoffs.
Wondolowski scored in the 87th minute to give the Quakes a 1-0 victory over Chivas USA on Sunday night at the StubHub Center.
The Quakes (12-11-8) extended their unbeaten streak in all competitions to a season-best five games -- and moved one point behind the Los Angeles Galaxy and the Colorado Rapids, who share fourth place in the Western Conference.
The fourth- and fifth-place teams in each conference will play an elimination game to determine which team will face the conference's top seed.
"It's really do or die," Quakes defender Steven Beitashour said. "We knew we had to come out with three (points)."
Helping the Quakes' chances were the Galaxy's and FC Dallas' losses Sunday. Dallas had trailed the Quakes and the Vancouver Whitecaps by one point as the day began.
The Quakes won despite playing with 10 men for the final nine minutes. Steven Lenhart received his second yellow card in the 81st for shoving his left forearm into goalkeeper Dan Kennedy's chest as both were in the air.
Lenhart will be suspended for the Quakes' next game, Oct. 9 against Colorado at Buck Shaw Stadium.
Nevertheless, Beitashour believes the Quakes are ready to make a late-season surge.
"We were fighting a lot of injuries in the beginning of the season, a lot of suspensions and a lot of international duty," Beitashour said. "Now, we have everyone back."
Wondolowski scored his ninth goal after Alan Gordon fired a 23-yard shot that Kennedy blocked with his chest. An onrushing Wondolowski converted the rebound from nine yards.
Jon Busch made two saves against Chivas USA (6-17-8) for his seventh shutout of the season.
Defender Clarence Goodson, suffering from a bruised right knee, did not travel with the team. Jason Hernandez started in Goodson's place.