Rochdale boss Brian Barry-Murphy was satisfied with his side’s overall efforts in the 4-1 defeat at Pompey.
But the Irishman pinpointed a lacklustre defensive display as the reason behind relegation-threatened Dale’s loss at Fratton Park.
Oli Hawkins’ header and captain Brett Pitman’s penalty handed the Blues a 2-0 half-time advantage in the League One encounter.
But Aaron Wilbraham was on hand to pull a goal back for Rochdale nine minutes after the break.
However, strikes from substitute Gareth Evans and star man Jamal Lowe wrapped up victory for promotion-chasing Pompey.
The defeat saw Rochdale drop to 20th in the table with four games to play.
They sit just a point and place above the relegation zone.
And boss Barry-Murphy wants Dale to learn their lesson following the defeat against Pompey.
He told the club website: ‘I thought it was a very difficult afternoon for us.
'I didn't want the way that we played and some of our good football to be an excuse for some of our defending as a team.
'I felt we didn't defend as resiliently and as resolutely as we have in previous games.
'That was the only disappointment of the day, for me.
‘The side they possess, they have the quality to score a goal in an instant.
‘They've got dangerous players in wide areas, we were fully aware of that.
'Parts of our game plan worked and we took wide players away from our goal.
'We caused them problems but we weren't able to convert our possession into chance, like they were.
'It can become really difficult at these places when you are 3-1, 4-1 down.
'I was pleased the players stuck in there and no more damage was done.
'There were a lot of lessons for to learn for myself and all the players moving forward.’