Playing at home Sunday, forward Tevenn Roux, with an assist from Austin Wehner, broke the scoreless tie for SDSU after the 101st minute – 62 seconds into the second OT.
A Stanford defender and the Cardinal goalkeeper tried to stop the pass, but it slipped between them to Roux, who scored his first goal of the season.
The Aztecs (5-0-2), ranked in the latest United Soccer Coaches Poll for the first time since 2016, logged their sixth shutout this year behind the work of goalkeeper Jacob Castro.
They haven’t trailed all season and rank in the top five in the nation in team goals against average (.184) and save percentage (.944).
This is also the first time SDSU has entered Pac-12 play undefeated since 2005.
SDSU, ranked No. 2 in the Far West, trails only Washington (5-0-0) in the region. The Huskies rank No. 3 in the country.
The Aztecs hosted Cal (2-3-1) in a 2-0 win Thursday. They struck early to score in the fourth minute when captain Andre Ochoa raced to beat a defender to a Laukoa Santos cross.
SDSU allowed Cal to attempt one shot in the first half and outshot them 11-8 on the night. The Aztecs added to their lead in the 66th minute on another Ochoa goal.
“The team brought so much fight,” Ochoa said of the victory over Cal.
San Diego State returns to non-conference play at 7 p.m. Friday when they host Gonzaga, again at home.