Colorado began the day as one of five teams separated by just two points who are battling for the final two playoff positions in the Western Conference.
Colorado took a 2-1 lead in the second period on goals from Cody McLeod and Muller before Hall knotted the score.
Varlamov made 28 saves. Nikolai Khabibulin stopped 30 shots for the Oilers, who have lost four out of five.
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