There is no need to get too negative after the recent series loss to Sri Lanka. Before the T20 series, Pakistan had won 39 out of 43 T20 matches and they were the no.1 T20 team according to the ICC rankings. Even now, they are the top ranking T20 side (comfortably ahead of the second placed England by a good 9 points) and their record stands at 39 wins out of the 46 recent matches.
However, it is going to be tight against Australia. But Australia seems to be in a lot of trouble as well. Apart from Steve Smith, none of the other batsmen are in good form. Even during the Ashes, it was the one man army of Smith which guided them to series win. Pakistani bowlers need to think how they are going to tackle Smith. If they can do that, then it's going to be their series.