Victory would have put Carl Veart's side in a strong position to secure a Finals spot and they were on course for all three points when Jordan Elsey made the most of some slack marking to head in Lachlan Brook's corner after 13 minutes.

Sydney was in danger of suffering a third consecutive defeat for the first time in seven years, Paul Izzo producing a good save to deny Milos Ninkovic an equaliser.

But the Sky Blues were level six minutes before the interval, Adam Le Fondre tapping in his 19th goal of the season after Izzo had come off his line but failed to stop Trent Buhagiar's cross.

Alexander Baumjohann and Riley McGree came close to winners in the second half but it finished level, leaving Adelaide in sixth ahead of their final match of the regular season against Melbourne City next week.

While Newcastle Jets cannot now catch the Reds, Western United could make up the five-point gap as they have three games in hand, while Western Sydney Wanderers have two extra matches in which to mount their own challenge.