The Panthers went on a 4-on-3 power play after the Capitals' Mike Green was whistled for holding in the extra frame and Wideman's wrist shot found the net, enabling the Panthers to break a three-game losing streak.
The Capitals earned a point in their ninth straight game despite the loss, going 6-0-3 over the span.
Marcus Johansson got a pair of goals, Mike Knuble added a tally and Michal Neuvirth turned aside 37-of-41 shots for Washington.
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