Lorenzo Burnet's first-half goal was enough to give FC Groningen a narrow victory that leaves their opponents deep in relegation trouble.
Burnet scored a much too simple goal in the 18th minute and Excelsior rarely looked like getting level in a dull affair.
The result leaves Excelsior in 17th place, only two points above rock-bottom De Graafschap and 10 points from escaping the relegation play-off places.
There was little sign of a team capable of climbing out of that hole before the season's end as Groningen were able to boss possession.
David Texeira might have had the visitors in front after only eight minutes as he broke through one-on-one, but Wesley de Ruiter made a good save with his feet.
However, the goalkeeper could not hold a shot from Petter Andersson which instead spilled into Burnet's path for a simple finish.
They might have made it 2-0 before the break as Leandro Bacuna saw a shot come back off the left-hand post, while Excelsior's first-half attacks were limited to a Roland Alberg shot from distance that went wide.
The hosts showed a touch more urgency late in the second half, but still offered little threat.
Kevin Jansen's shot from the edge of the area went over, while a Mitchell te Vrede effort also swerved off target.
Groningen goalkeeper Luciano da Silva was elevated from his role as a spectator for the first and only time in the 74th minute when he comfortably held Rangelo Jango's timid header.