View the photos from the Blues' League One win at Highbury Stadium
Pompey made the long trip back south from Fleetwood on the back of a 2-1 victory.
Jamal Lowe ensured they led at the break after Ben Close's initial shot had been blocked inside the box.
And when Alex Cairns could only parry the winger's cross, Oli Hawkins followed up to double the visitors' advantage.
A stunning Conor McAleny strike reduced the Cod Army's deficit, but the Blues held on to secure all three points.