Many of Penedo's saves were spectacular, including one on Seattle's Andy Rose early in the second half on a shot Penedo later admitted he didn't even see.
"I honestly don't know how I saved that one," said Penedo, who fell one stop short of Kevin Hartman's 12-year-old team record for saves in a game. "The ball just came and I happened to be just standing."
The shutout, Penedo's 13th in 41 MLS games, upped his record with the Galaxy to 20-9-12 in parts of three seasons. He has a career 1.05 goals-against average.
"He kept us in the game," Galaxy defender Omar Gonzalez said of Penedo. "You know when your keeper makes those key saves, those brilliant saves that keep the game at zero-zero, it just gives you an opportunity to make something happen. Sure enough, after Jaime made those saves we figured out a way to score.
"We go up 1-0 and later in the game he makes some more key saves. Jaime Penedo played brilliantly."