The home side lead at half time thanks to Sykes, but a penalty won and converted by Sofia Huerta brought the visitors level in the 65th minute.
Sykes scored a majestic second in the 79th minute to restore her side's lead, but Huerta responded with a fine solo goal just moments later to ensure the points were shared.
Sykes had two goals disallowed in the opening period for offside, but finally got her name on the board after 20 minutes, as Grace Maher made space down the left before cutting the ball back for the captain to tuck home.
The home side continued to create the majority of the chances for the first half, but struggled to find the finishing touch as a number of shots went sailing over the goal.
Adelaide looked to create but struggled for the most part to break down the home defence, with Racheal Quigley a subdued force in the first 45 minutes.
Both sides came out of the break slower as the heat began to die off, with chances not forthcoming in the opening few minutes.
The game began to open up however and the introduction of Lisa De Vanna for Canberra gave the game a bite of energy.
Adelaide finally had their big chance after 64 minutes, as Jenna McCormick's risky challenge felled Sofia Huerta in the box for an Adelaide penalty.
Huerta made no mistake on the spot kick as she tucked it away low and hard to put the visitors back on level terms.
Canberra thought they had taken the lead again in the 70th minute, but Jasmyne Spencer's tap-in was ruled out by the assistant referee.
With 12 minutes to go however, Sykes picked up the ball outside the area and curled a fantastic shot into the corner out of reach of Sarah Willacy to retake the lead.
It took Adelaide merely two minutes to restore parity at 2-2, with Huerta's outstanding solo run and thunderous strike levelling the game up.
The closing minutes saw Canberra pile forward in search of a winning goal, but despite chances for the likes of Raso, De Vanna and Sykes the home side could not find a way past the resolute Willacy.
Canberra United face Perth Glory at home next week in a crucial clash, while Adelaide will take on Western Sydney Wanderers in the City of Churches.
This article was originally published at: http://www.canberraunited.com.au/article/canberra-united-and-adelaide-united-play-out-2-2-draw-in-the-capital/wo0kpg9zleje14h4tpjhgaljv.