On 24 February 2010, a friendly between the Philadelphia Union and the Atlas U-20s ended early when hostilities erupted on the pitch.
The Union were down in Guadalajara to prepare for their first MLS season and scheduled the friendly against the U-20 squad of local team Atlas. But the match failed to love up to the name, with a total of five ejections--three Union players and two from Atlas.
Tempers continued to flare to the point where the referee ended the match with twelve minutes left in order to avoid an incipient riot. Atlas still got the win, though, 3-2.
The match set the stage for the Union's season, as they finished with the league's third-worst record (just above Chivas USA and DC United) and failed to qualify for the MLS Cup playoffs.