Johnny Gaudreau scored the only goal of the first period of the World Junior Championship quarterfinals to give the United States a 1-0 lead.
Gaudreau scored on an easy tap-in on a 5-on-3 penalty at the 11:45 mark of the first. The Czechs had taken back-to-back hooking penalties to go down by two skaters. Gaudream made them pay with his third goal in two games and the Americans' fifth power-play goal in the past four periods. The United States had four man-advantage goals in a 9-3 win against Slovakia on Monday.
The winner of this game plays Group B champion Canada in the semifinal on Thursday.