Amari Williams blocked a shot that ignited a Drexel celebration — yellow and blue streamers were chucked on the court — decades in the making for a program long the outsider on the Philly hoops scene. The Dragons — with all of five total NCAA Tournament appearances — crashed the City Series this season and showed life in a reimagined pseudo-conference can be pretty glorious in the present, too. Williams scored 12 points, grabbed six rebounds and blocked No. 18 Villanova’s tying-attempt with 3 seconds left to help Drexel upset the Wildcats 57-55 on Saturday in the inaugural Big 5 Classic at the Wells Fargo Center.