In 2007, in his debut season at the University of Portland, Guerrero was named to the Copa de Causeway All-Tournament Team and won WCC League Player of the Week honors on October 8, registering 9 saves in a shutout against San Diego. At one point, he held a scoreless streak of 435 consecutive minutes without allowing a goal. Ultimately, Guerrero led the Portland to an NCAA playoff appearance after leading the WCC in shutouts (8) and saves (85). He was named to the All-WCC First Team and All-Freshman team, in addition to being named to Soccer America's National All-Freshman Team, Top Drawer Soccers National All-Rookie Team, and College Soccer News National All-Freshman Second Team. At the end of the season, Guerrero was called into the United States Under-20 National Team camp to play Honduras.
