In May 2003 Scott Lost, Disco Machine, Excalibur, Joey Ryan, Super Dragon and Top Gun Talwar, known collectively as the "PWG Six", founded SoCal promotion Pro Wrestling Guerrilla.

[7] They did however win the PWG Tag Team Championship at the next show by defeating inaugural champions Homicide and B-Boy,[8] but could only hold them until the following month, before losing to Chris Bosh and Quicksilver.

They faced champions Super Dragon and Davey Richards on February 19, 2006, at European Vacation - England, but were unable to regain the titles.

[17] 2008 started off with Lost and Joey Ryan being awarded the PWG World Tag Team Championship on January 27 after the previous champions Super Dragon and Davey Richards failed to defend the titles against them on three occasions.

Prior to the 2009 Battle of Los Angeles Lost went on a winning streak and defeated El Generico,[21] Colt Cabana,[22] Human Tornado[23] and Joey Ryan[24] in singles matches, only to lose to eventual winner Kenny Omega in the quarter-finals of the actual tournament for the vacant PWG World Championship.

[25] On Friday, January 29, 2010, Scott Lost competed for the wrestling promotion Ring of Honor, when they made their debut in Los Angeles, California, as part of the WrestleReunion 4 convention.

[27] On June 28, 2010, PWG announced that Lost would be wrestling his retirement match on July 30 at the company's seventh anniversary show, where he will face longtime rival Scorpio Sky.