Sunderland headed to Villa Park on the back of two straight wins, but missed out on the chance to all-but secure Premier League survival after being torn apart by a rampant home side.
The result leaves both teams on 37 points, five points outside the bottom three, and Di Canio was left to reflect on a 'humiliation'.
"It's a very bad defeat and our performance I'm not very happy about, obviously, but probably we thought the main job was done," Di Canio told Sky Sports.
"If the team has performed in this way, the first person responsible is the manager, and also the players, but the signals we probably didn't read in the week.
"Maybe this is a medicine in some way that can let us understand that we have to play with desire, commitment, otherwise we are going to have difficulty.
"This humiliation can help the players, the manager, the staff. We need a minimum of another three points. We can do it, but it was unacceptable the performance we made tonight.
"There was one team that played like it was the last chance of their life, which was Villa, and a team that was probably a little full in the stomach because of the last two wins in a row."
Sunderland saw Sessegnon sent off with 20 minutes to go for catching Yacouba Sylla with a late tackle, but Di Canio will challenge the three-match suspension which would rule the playmaker out for the rest of the season.
The Sunderland boss added: "We saw the clip and there is not a bad challenge. In my opinion it wasn't a red card.
"I think once the referee has seen the clip he's going to realise the dynamic of the challenge can put him in difficulty.
"In reality, when you see the clip there isn't any intention to damage the opponent. The leg was not raised. We're going to appeal, of course."