كتب : Omar AbdelAziz
Badar Al-Maimani put the Arab side ahead in the 31st minute with a low shot, but Cahill saved Australia's blushes after the Oceania nation looked set for an Asian cup debut defeat.
Bolton Goalkeeper Ali Al-Habsi blocked Mark Bresciano's initial shot, but Cahill tapped in from close range for the late equalizer.
The Omani team wasted a host of chances to double the lead, but they were repeatedly denied by Middlesbrough keeper Mark Schwarzer.
All Group A members tie at one point each, after Thailand and Iraq registered the same 1-1 score line in the tournament's opener on Saturday.
In group B, hosts Vietnam stunned Gulf Cup winners United Arab Emirates 2-0. Huynh Quang Thanh broke the deadlock in the 63rd minute with a volley after a mix up in the UAE defense.
And while the Emirates were trying to get back in the game Le Cong Vinh secured the victory by springing the offside trap and playing a beautiful lob from outside the area to snatch his side their first ever points in the competition.
Vietnam, who make their first ever appearance in the Asian Cup, are now on top of the group waiting for the result of holders Japan who will take on Qatar on Monday.