Arabian Gulf League side Al Ain held Saudi rivals Al Hilal to a goalless draw in the first leg of the 2017 AFC Champions League quarter-finals at Hazza bin Zayed Stadium.
Despite playing with ten men for nearly half an hour after Mohanad Ghazy's sending off in the 66th minute, the hosts were able to see out the 0-0 result.
Douglas foudn the back of the net from an Omar Abdulrahman cross from the left flank 24 minutes into the first half as the crowd erupted but were quickly left disappointed as the linesman ruled the Brazilian offside.
Khaled Essa saved Mohamed Al Braik's free-kick in the dying seconds of the first half as the teams went into the break level.
Abdulrahman sent a curling free-kick destined for the top corner, but Al Mayouf tipped his effort over the bar on the hour-mark.
Al Ain's fortunes suffered a blow when defender Ghazy was sent-off halfway through the second interval after the referee deemed his challenge on Salman Al Faraj worthy of a second yellow card.
Al Hilal's most dangerous chance of the match came in the 75th minute when playmaker Carlos Eduardo found teammate Matias Britos with a pinpoint cross from the left wing, but the Uruguayan striker failed to get his head onto the delivery and Essa collected the loose ball.
Douglas was denied a golden chance to seal the tie for Al Ain when his 86th minute header was brilliantly saved by goalkeeper Al Mayouf.
The striker was replaced by Mohamed Khalfan as the game at Hazza bin Zayed Stadium ended goalless. Al Ain travel to Riyadh in three weeks' time hoping to snatch a semi-final ticket.