The Blackhawks played in Philadelphia for the first time since the 2010 Stanley Cup Finals, which Chicago won in six games.
Patrick Kane, who scored the game-winning goal in the Stanley Cup-clinching victory 19 months ago, was sent to the penalty box Thursday with 1:38 remaining for high-sticking.
Van Riemsdyk took advantage by scoring his 11th goal of the season and bringing Philadelphia its second win in three games. He also scored the last of three unanswered goals in the second period to put the Flyers in front 4-2.
Chicago rallied to tie it in the third period on goals from Brent Seabrook and Kane in a span of 35 seconds.