Indonesian players should be forget this result and focus for upcoming match against China and so far China is the weakest team in group C because until 3 matches they still unable to collect points and hopefully this time Indonesia can beat China and gets 3 points from this match
I'm pretty sure that's what the captain said in one of the interviews. He said in football you can't expect fairness to win you the game, so they need to move on and prepare for the next match asap. I think the chance for them to go to the next round is still high anyway since they will face Bahrain again in Jakarta. Who knows maybe they'll get another 3 points from Australia or Arab too, or steal another point and finish with 10 points or so. It's still too early for them to give up.
I am sure they can maintain their mentality very well, even this very disappointing result can be a motivation for them to be more effective. I think it will be a different story when they can take advantage of the opportunities that occur in extra time, and if it can be used as a goal then it will be a game killer. Indeed, in football you cannot expect to get the fairest justice, sometimes that factor makes the results not in accordance with expectations. I even saw an official post from Bahrain noting that the goal they created occurred in the 90+6 minute, it was very funny. This is a lesson for Indonesia that when they have improved there are things that will bother them.