Cassisi (36 disposals, eight tackles and eight clearances) led from the front against the Dees at the MCG, but few of his teammates followed.
The players were ordered to Grange for a 6am beach session on Monday as punishment for the result and Cassisi said the performance was simply not good enough.
“There was so much on the line. We keep talking about how tight the ladder is and the positions of all the teams around the eight,” Cassisi said on Monday.
“It was a big game for us coming off a good win against Brisbane last week and there’s no need to beat around the bush- it was a poor effort.
“We’re ready for a tough week and we’ve got to turn it around this week and show our supporters that we do care.”
Cassisi lamented his side’s effort and skill level following the upset loss that lifted Melbourne off the bottom of the AFL ladder.
“Melbourne outnumbered us [around the ball] and that might come down to a work rate thing. We’ll look at the footage today and when we do all the ugly stuff will rear its head,” he said.
“If we’ve got more midfielders not bringing their best than we have guys that are, it makes it a battle. In the midfield, you need all your midfielders firing to get the result.”
The Port Adelaide midfield should be bolstered by the returns of Matt Thomas and Travis Boak.
Thomas pulled up well after playing just over a half for the Norwood reserves, while Boak (knee) trained strongly last week and will be tested on Wednesday.
Hamish Hartlett (hamstring) is still a couple of weeks away from a return and Daniel Motlop (ankle) is likely to miss another month.
Port Adelaide’s poor percentage (91.9) means it will have to win five or, possibly even, six of its remaining seven games to feature in the finals.
The Power have not recorded consecutive wins since rounds three and four this season.
Cassisi said his side had to put an end to its roller-coaster year starting with a win over West Coast at AAMI Stadium on Sunday.
“We’ve still got a lot of games at home, but we’re not looking past this week. We just have to focus on West Coast,” Cassisi said.
“They put up a good fight against St Kilda and we need to make sure we’re doing everything right this week and that our effort can’t be questioned on the weekend.”
