The Lightning stopped a three-game losing streak and climbed within eight points of the final post-season berth in the Eastern Conference. Tampa Bay has only nine games left in which to make up the difference.
Tampa Bay's Steven Stamkos kept the shootout going with a goal in the third round and both teams produced a score in the fourth. After both skaters missed in the fifth round, Purcell finally won it with a shot lifted over Nikolai Khabibulin.
Tom Pyatt scored both regulation goals for Tampa Bay and Dwayne Roloson made 34 shots to get the victory.
Khabibulin stopped 19 shots for the Oilers, who are out of playoff contention.