An uninspired Australia were facing World Cup embarrassment against the Thais before Osieck hauled off Cahill with 20 minutes to run. Alex Brosque managed to scramble home an ugly winner in front of 25,000 fans at Suncorp stadium.
"Josh (Kennedy) and Tim (Cahill) are too similar," insisted Osieck, "they neutralised themselves and it was not beneficial for the team.
"This is why I took off Tim and replaced him. I felt we needed something different with Josh.
"I am happy Alex came on and scored the goal, it was a tough, difficult call, but it had to be made."
On the overall performance, Osieck added: "I expected a tough game. I know from experience, the first game of qualifying is always difficult. The boys didn't play the way I wanted. There were too many square balls, too many touches in midfield that gave them (Thailand) the chance to get back."
"There's no excuses.
"We were all over the place and we didn't have any real shape."