Tracy, who was projected to be a high MLS draft pick before indicating his desire to play in Europe, scored in the 68th minute. Fellow American Danny Califf, who was called in by the USA for its upcoming World Cup qualifying games, did not see action for Midtjylland.
Tracy helped the Demon Deacons to the 2007 national championship, scoring both goals at the Men's College Cup semifinals and the tying goal against Ohio State in the final.
Last week, Tracy came on in the second half of Aalborg's match against Manchester City in the second leg of the UEFA Cup's round of 16. With Tracy on the field, Aalborg scored two late goals -- the first set up by Tracy -- to tie the series on aggregate, but Man City prevailed in a shootout.
Houston picked the Connecticut product in the fourth round of the SuperDraft after it was known he wasn't likely to sign with MLS.
Aalborg, defending Danish champ, is currently in fifth place.