Stuart O’Keefe spoke of his disappointment at letting Pompey’s travelling faithful down.
The Blues signed off on the road for the season with a dispiriting 1-0 loss to a Bury side already relegated to League Two.
The bottom-of-the-table outfit were good value for their victory, on a day results confirmed Kenny Jackett’s men will be in the third tier next season.
The 1,525 travelling fans deserved to see better from their side after making the 500-mile round-trip to the north west.
O’Keefe knew they had been let down – and he and his team-mates had not done enough for their followers.
He said: ‘We know we bring good backing every week and to send them home disappointed is not what we want.
‘We want to put on a performance and ultimately get a good result for them
‘It was lacklustre and we weren’t sharp enough.
‘We looked lethargic and it showed against a team with nothing to play for this season.
‘They are relegated and their confidence was at a low to begin with.
‘But we let them get the goal and allowed them to get some confidence. We made it hard for ourselves.
‘It was against a team who was down and that’s a disappointment for us.
‘We have to just make sure we come back now and give them something to cheer about next weekend.
‘We want to give the crowd a reason to create a good atmosphere against Peterborough.’
The game’s key moment arrived in the 67th minute when a gaffe from Luke McGee gifted the Shakers victory.
The keeper dallied on a backpass from Matty Kennedy and allowed striker George Miller to nick the ball away from him and fire into an empty net.
O’Keefe explained McGee was big enough to accept the fault for defeat lied with him.
He said: ‘Luke’s held his hand up.
‘He’s been around long enough to know he messed up.
‘He’s obviously very disappointed but he’s performed well for us this season.
‘We need to be better collectively and make sure we build for next year.
‘That’s what it’s all about.
O’Keefe knows Pompey now owe it to their players to put in a performance as the curtain comes down on the season against Peterborough.
The midfielder is aware his side’s supporters have continually backed his team and deserve a reason to smile at the end of the campaign.
He said: ‘We need to show our supporters we didn’t want this season to fizzle out.
‘Our supporters have been fantastic all season and we need to finish on a high for them.
‘They’ve got behind us no matter what - so we have to give them something more against Peterborough.
‘I want to finish off on a positive.
‘I don’t want to finish off with four defeats in a row.
‘I want to finish off on a positive and help people to feel good going off into the summer.’