More than 1,500 fans made the long trip north to Bury for Pompey’s final game on the road this season.
But all they received for their efforts was a laboured Blues display that resulted in a 1-0 defeat to a side who will finish rock bottom of League One.
George Miller capitalised on a mistake from Luke McGee to grab the only goal in the second half at Gigg Lane.
And Stuart O’Keefe was frustrated that Pompey were unable to carve open many clear-cut chances against the Shakers.
The midfielder said: “We brought good numbers here for the last away game of the season and it’s a disappointing way to finish.
“Everyone is looking to end on a high and unfortunately, for whatever reason, it didn’t happen on this occasion.
"We weren’t slick or ruthless enough against a team who perhaps had the shackles off with nothing to play for."
“Luke held his hands up. Errors are part and parcel of football and you just hope to eradicate as many as you can.
“We looked a bit lacklustre – we weren’t slick or ruthless enough against a team who perhaps had the shackles off with nothing to play for.
“We had good control of the game and spent a lot of time in their half, but our final ball just let us down.
“If we’d taken a bit more care in possession then we might have opened them up and the chances would have come more freely.
“Hopefully we can put it right next Saturday because we don’t want to finish the campaign with four losses in a row.”
Despite a disappointing end to their season, O’Keefe believes that the future is still bright for Pompey.
He said: “You look at the numbers we bring to every away game and then have 18,000 for all our home matches.
“So this club definitely has something going for it and with the right squad and mentality, it can really go places.”