Blackhawks goalie Corey Crawford made a save on Daniel Sedin's shot from the slot but was left helpless when Samuelsson picked up the loose puck and backhanded it into an open net, breaking a 2-2 tie 6:48 into the third period.
Sedin and Christian Ehrhoff each notched a goal and an assist, and Henrik Sedin added a pair of helpers for the Canucks, who will look to sweep their Western Conference quarterfinal series against the defending NHL champs Tuesday in Chicago.
Roberto Luongo turned aside 30-of-32 shots in Vancouver's victory.
Duncan Keith and Patrick Sharp each scored power-play goals for the Blackhawks and Crawford finished with 23 saves.
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