The game endured a slow start as both teams looked to grab a hold of possession, while both failed to churn any of it into any notable chances.
Brandley Kuwas had the best chance of the first half to break the game's deadlock, as his left-footed strike destined for the top right-hand corner was palmed behind by Robbin Ruiter to keep the scores level.
However, after both sides failed to create any meaningful chances, the game's breakthrough came when Willem Janssen brought down Stans inside the area to give the hosts the chance to make it 1-0.
The midfielder stepped up and put his spot kick into the top left-hand corner, giving Excelsior the lead in the 74th minute.
The win is only Excelsior's second victory of the season, leaving them 12th in the table.
Utrecht remain in 10th, only a point ahead of their opponents.