You can, and it would be stupid to say Barcelona have no chance of winning but as I said in that post, Barcelona's problem has been more than just a lack of motivation. They'll need to up their game, and can obviously do so, but it's not a switch you turn on. They were motivated today and couldn't win, and have been in the same scenario many times this season (including against Atlético). They don't control games as well as they used to and they don't break down defences as well as they used to either. Most of their players are out of form too.
Barcelona will dominate possession and Atlético couldn't stop that even if they wanted to - can Barcelona stop leaking chances though? I've only seen the highlights but even today they looked as likely to concede as they did score, so I'm ok at not sure it's curtains if you go one goal up.