Canberra stun Perth to win W-League
The win at nib Stadium marked United's second title, adding to their 2011-12 success.
It brought a disappointing end to the Glory's dominant campaign after they finished 10 points clear at the top in the regular season.
American Stephanie Ochs opened the scoring for the visitors with a long-range effort before Collette McCallum responded for the Glory.
But Sykes would be the hero.
She restored Canberra's lead in the 75th minute before heading home moments later to seal Canberra's win.
United's Grace Gill had a late penalty saved, but it did not matter.