Erwin Koeman's men finished 16th in the Dutch top flight this season, three points adrift of safety.
And, after overcoming De Graafschap in the the second round of the play-offs, RKC are on the brink of succumbing to the drop following a disastrous first-leg performance in Rotterdam.
Anything other than a defeat by two or more goals on Sunday will make sure of Excelsior's place in the top tier, however they are not the only Rotterdam club vying for promotion.
Gert Kruys' side relegated NEC by beating them 4-1 on aggregate in the second round of the play-offs, and demonstrated their resolve to come from behind twice to earn a 2-2 draw with Dordrecht in the first leg of the decisive tie on Thursday.
Jaime Bruinier's 80th-minute strike salvaged a draw for Sparta, however, it is Dordrecht who have the advantage on away goals and should be the firm favourites heading into the second leg.
"Sunday afternoon we will have a full house and we can use the support of the fans well," Van de Looi told Groningen's official website.
"That should be an advantage for us. But let us not be fooled and play football like headless chickens.
"It is wonderful that we are up to the last game in the race for the last European ticket."
