Wondolowski broke away from his marker and deftly redirected a 61st-minute corner kick from Marin Chavez to complete San Jose's rally from a 3-1, first-half deficit.
David Beckham and Landon Donovan sandwiched scores around an own goal by San Jose defender Jason Hernandez in the space of 10 minutes to put Los Angeles (6-9-2) ahead by two goals, but the Galaxy had their three-game winning streak broken when they couldn't hold that lead.
Bernardez hammered home a Chavez corner kick with a full-blooded volley in the 44th minute to bring San Jose within a goal at the half.
Lenhart opened the scoring in the seventh minute by tapping home a loose rebound spilled by Saunders, who couldn't handle a dipping drive from Chavez.
Backup San Jose goalkeeper David Bingham, pushed into action after starter Jon Busch suffered a swollen eye in a collision with Bernardez, pushed aside a 74th-minute shot from Beckham.
Earthquakes left back Justin Morrow snuffed out a pair of chances in the 85th minute, walling off Galaxy substitute Chad Barrett to prevent him from reaching a loose ball on the doorstep, then blocking a shot by David Junior Lopes.
Donovan scored his fourth goal in the past three matches to put Los Angeles up 3-1 in the 41st minute, completing a sequence initiated by an ill-advised back pass from Hernandez.
Hernandez also put the ball in his own net in the 36th minute, trying to deflect a cross from Hector Jimenez.
Beckham delivered a scintillating free kick in the 31st minute, leaving Busch flat-footed, to make it 1-1.
The game drew 50,391 to sold-out Stanford Stadium.
- San Jose Earthquakes
- Los Angeles Galaxy
- Victor Bernardez
- Chris Wondolowski
- San Jose
- David Beckham
- Steven Lenhart
- Los Angeles
- Jason Hernandez
- Landon Donovan