Watch key moments from League Two triumph
Conor Chaplin came off the bench to secure victory for Pompey at table-topping Northampton.The teenager netted with his first touch after goalkeeper Adam Smith could only parry a shot from Ben Tollitt.
Gareth Evans had earlier headed home Marc McNulty's cross to cancel out Ryan Cresswell's opener.
Watch the key moments from the game below or subscribe to Pompey PlayerHD for extended highlights.