Australia surged to a 2-0 lead at the break before piling on three more goals in the second half to secure a thumping 5-1 win.
Steve Kuzmanovski scored a brace for the Aussies while skipper George Blackwood, Keanu Baccus and Joseph Champness all found the target as Ufuk Talay’s side cruised to victory.
The Young Socceroos’ victory turned around the result from earlier in the tournament, with Thailand emerging 5-1 winners in the group stage.
“There’s no easy games. Thailand is a good team. We set up a little bit differently from the first time we played them in the group stage,” Talay said.
“We created a lot of opportunities in the first half. I think we could have been up 6-0 at half-time but we didn’t convert.
“I think the boys were very disciplined when we didn’t have the ball. Overall, I thought it was a good game for us.
“For us, to come to the AFF [tournament] it was very important to get quality games.
“We got seven quality games. It was very important to not focus on the result but focus on the performance leading into Bahrain [AFC U-19 Championships].”
Australia stormed out of the blocks in the opening half with Keanu Baccus finding the target with a header in just the 10th minute after a lovely corner from Connor O’Toole.
Steve Kuzmanovski doubled the advantage less than 10 minutes later with the Melbourne City attacker calmly slotting home after a well-weighted cross from Joseph Champness.
The Aussies continued to create a number of opportunities but some wasteful finishing and some excellent saves from the Thai keeper kept the score at 2-0 at the interval.
But the floodgates opened after the interval with Australia netting three goals in six minutes midway the second-half to kill off the contest.
Blackwood slotted Australia’s third in the 67th minute after being picked out by Baccus before Champness profited from a Thailand mistake to make it 4-0 just three minutes later.
Steve Kuzmanovski completed his brace in the 73rd minute to make it 5-0, with Australia punishing Thailand on the counter attack after committing numbers forward.