Socceroos coach Ange Postecoglou had stressed the friendly matches were about challenging his squad and blooding new players but admitted he had to take responsibility for the disappointing result.
"I keep saying I'm making these decisions and I'm making them for a reason and that's probably costing us in terms of performance and in terms of fluency," Postecoglou said.
"But it is what it is and I take responsibility because I'm making these decisions."
Australia could not put away several clear-cut chances and Postecoglou felt at times his side played "some of the best football we've played for a while."
"We just spoiled it by conceding a sloppy goal," the coach said.
"We were in control of the game and we paid a heavy price for it. It was a frustrating night."
Postecoglou now has plenty to ponder ahead of next month's friendly away to Japan, Australia's final warm-up for January's tournament.
The coach made eight changes from the side that drew with the UAE, giving starts to the recalled Nikolai Topor-Stanley and Aziz Behich in defence, Mitch Langerak in goals and James Troisi in midfield.
Cahill was restored to the point of attack after coming of the bench against UAE and he set up the best chance of the first half for Troisi, whose driven shot was saved by Qassem Burhan in the 21st minute.
Josh Brilliante came on just after halftime for captain Mile Jedinak with Adam Federici getting a shift in goal and Australia came close again in the 51st minute with Robbie Kruse forcing a good save out of Burhan.
Just as it looked as if the Socceroos were taking control of the match, Qatar went in front.
A Chris Herd clearance across the face of goal handed the hosts the ball in a great spot and the Socceroos couldn't clear from a scrappy exchange, with Ibrahim sweeping the ball into the net.
Postecoglou responded by replacing Herd with Ivan Franjic while Bernie Ibini came on for Kruse, who encouragingly played another full hour to continue his comeback from knee surgery.
Postecoglou used a 75th-minute drinks break to address his side passionately in a huddle before throwing Mathew Leckie and Brad Smith on late.
Smith had the best chance to equalise in the dying minutes but scuffed his shot from close range as the Socceroos fell to a side they have dominated in the past.
"It's a little bit of a setback but for me it's all about education and I think tonight we definitely learned a lesson," Cahill said.
AAP lf/jb
-AAP
