Jan Wouters' side completed a third straight victory as Gevero Markiet and Steve De Ridder scored in the second half.
However, there could have been a different story had Michael Higdon not missed a penalty for NEC, who remain rooted to the foot of the table, with the score at 1-0.
Neither side was able to find the breakthrough in a tense opening period at the Stadion Galgenwaard.
The hosts took the lead in the 48th minute through an unlikely source in the shape of full-back Markiet, who bagged his first league goal of the season.
Things got worse for NEC when Ryan Koolwijk received his marching orders for a second bookable offence in the 67th minute.
Yet Anton Janssen's charges could have drawn level with 15 minutes remaining, only for Hidgon to fluff his lines with a spot-kick.
The visitors were left to rue that missed opportunity, as just three minutes later De Ridder made sure of the points for Utrecht.
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