Richards took a backhanded pass from Kimmo Timonen high in the slot and put a slap shot past Mike Smith.
The Lightning missed an opportunity to win with 16.3 seconds left in regulation when Ryan Malone was awarded a penalty shot, but he pushed the attempt wide of the net. Malone had hit the post on a breakaway, and was given the penalty shot when Philadelphia forward Scott Hartnell threw his glove at the puck.
Jeff Carter scored the other two Philadelphia goals and added an assist for the Flyers, who had won six straight before dropping their previous two games.
