Karl Robinson’s side had won 11 of their previous 14 matches heading into tonight’s Kassam Stadium encounter.
The Blues have rightly come under heavy fire in recent weeks following four defeats in seven fixtures, including Saturday’s 1-0 loss to Blackpool.
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That awful form has seen them fall behind pacesetters Peterborough, Hull and Lincoln, who have now emerged from the pack.
But the players responded in tremendous fashion at Oxford to demonstrate their promotion credentials once more.
And Pompey are now fourth in the table.
Assistant boss Gallen told The News: ‘It was a fantastic performance from the players, I thought they played very well.
‘They showed a lot of tenacity, it was a good intense performance, we ran, chased and harried and at times showed composure on the ball and played some good football.
‘Personally, I believe in the players and the reason for that is because I know that they believe in themselves.
‘A couple of times this season we’ve had poor results and managed to pull out a big win.
‘This is undoubtedly a big win coming to Oxford. It’s very tough, they have some good players, an experienced manager and we’ve had some tough games against them.
‘But knowing the character, the belief and how our players really want it – I think that really showed that against Oxford.’
With Hull losing at home to Ipswich, Lincoln held by Swindon 2-2 and Doncaster not playing, the Blues are now six points adrift of the automatic promotion spots.
However, ominously, Peterborough registered another win to top the table, this time overcoming Plymouth 3-0.
Next Pompey face Gillingham at Fratton Park on Saturday.
And Gallen is well aware they need to maintain a winning streak if they are to apply pressure to the top of the league.
He added: ‘I thought we deserved to win, but one win is not enough.
‘We need to get on a run of wins, so we’re looking forward now to Saturday.’
A message from the Editor, Mark Waldron
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