Australia somehow managed to win the match by two wickets only. It was a batting friendly pitch and Sri Lanka had set a good target too. The DLS method had made the game more favourable for Sri Lanka. But Stoinis has played well in the middle over and Maxwell has finished the game in his style. However, it was a competitive game in the last few overs as Australia had only two wickets left.
Sri Lanka has once again performed poorly in ODI format, and that too playing at home. Fortunately for them, this series is not part of the World Cup Super League, else they would have been in big trouble. Still, there is a very slim chance that Sri Lanka would be able to secure automatic qualification to the world cup, because they just have 62 points from 18 matches. Giving a good fight to their opponents won't help them in the long term. They need to win matches against the big 3 teams, and that's all that matters.
I actually don't think that Sri Lanka played that badly. I actually think they have done well enough in the batting department but yes, in the bowling department, the performance of Sri Lanka was questionable.
Except for Wanindu Hasaranga, no other bowlers of Sri Lanka were able to perform well and Australia really took advantage of that.
Sri Lanka had good enough runs on the board. Right now I don't see them winning against any bigger team.