Both sides struggled to keep their emotions in check as tackles flew in at Hazza Bin Zayed Stadium to the detriment of the host - runners-up last year - who played the final 24 minutes a man down and failed to take a lead to next month's return leg in Saudi Arabia.

There was a bright start to proceedings as first Omar Kharbin had a goal disallowed for the visitor, before Al Ain's Douglas was also denied by the offside flag.

The home side started to take control as the first half wore on and visiting goalkeeper Abdullah Al-Mayouf, largely untroubled besides Douglas' effort, had to be alert to make a smart stop from Omar Abdulrahman - the competition's top scorer this term - shortly before the interval.

Another smart Abdullah save from the same man followed after the restart, but Al Ain were dealt a blow when Mohanad Salem - already on a booking - lunged in late on Salman Al Faraj and saw red.

But Al Hilal could not make their numerical advantage count and were instead grateful to Abdullah once again as he clawed Douglas' header clear late on to preserve parity.