Doeschate (2/9) took two wickets when Volts restricted Maroons to 154 for nine and then smashed a stroke-filled 64-run knock to help his side overhaul the target with 12 balls to spare.
The New Zealand side now has two victories from as many matches and they play their final match against Sunrisers Hyderabad on Friday.
After today's defeat, the doors have virtually been shut on the Maroons of advancing further in the League. They had lost their opening match to Hyderabad side yesterday.
In Otago's chase, 33-year-old Dutch anchored his side's innings after they had lost top order batsmen Hamish Rutherford (20), who was in good form today, Brendon McCullum (8) and Neil Broom (25).
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Doeschate, Otago's top run-scorer in the HRV Cup, came in for Aaron Redmond who failed with the bat in the first match.
His knock of 64 came off in just 32 balls and was studded with two boundaries and five sixes.
Doeschate presihed when Nuwan Kulasekara caught him brilliantly at the boundary off Dilhara Lokuhattie but by that time he had steered Volts closer to the win.
Dilhara (3/20) was the most successful bowlers for the Maroons with three wickets.