Central Coast Mariners booked their spot in the A-League semi-finals after earning a slender 1-0 victory over Adelaide United this morning.

Bernie Ibini's 67th-minute winner proved the difference between the sides as the Mariners set up a last-four meeting with Western Sydney Wanderers next week.

It was the visitors who came closest to breaking the deadlock as Sergio Cirio fired into the side-netting on 49 minutes.

Then, Ibini opened the scoring for the hosts midway through the second half after beating goalkeeper Eugene Galekovic at his near post.

Adelaide came close to drawing level in the dying stages through Bruce Djite, only to be denied by the left hand of goalkeeper Liam Reddy as the Marriners held on.