Tampa Bay also got goals from Eric Brewer, Vincent Lecavalier, Victor Hedman and Steven Stamkos. St. Louis has eight assists and 11 points this season.
The Lightning continued their season-long domination of the third period - outscoring opponents 13-1 - with goals by Hedman and Stamkos.
Sean Couturier scored for the Flyers, who were coming off a 7-1 win at Florida on Saturday night. Backup goalie Michael Leighton played in his first NHL game since appearing in two playoff games for the Flyers in 2011.
Purcell tied it at 1 on the power play at 14:34 of the first.
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