Saturday's game was the third in the league for the Californian team who also has Jeppe Tverskov in their squad.
With the game seemingly headed for a draw, Dreyer gave the visitors a 2-1 lead when a clearance landed at his feet inside the box and the former Danish international wasted no time rifling hom from close range.
With his third goal of the season, he became the first player in league history to score two game-winning goals within the first three matches of an expansion club’s opening season.
Ingvartsen then scored his first goal of the season when he he was put cleanly through on on goal to make it 3-1 shortly before the end.
26-year-old Anders Dreyer, who has played three internationals for Denmark, transferred from Belgian Anderlecht to San Diego this winter.
The Danish winger already made a mark from the start when he scored twice in the 2-0 win over the defending MLS champions from Los Angeles Galaxy at the end of February.
It is no coincidence that the newly established MLS club has several Danes in the squad as one of San Diego's sister clubs is FC Nordsjaelland.
Both clubs are part of the Right to Dream organization, which, in addition to FCN and San Diego, also includes academies and clubs in Ghana and Egypt.
After tonight's game, San Diego is second in the western half of MLS.