Sean Raggett headed Pompey into a 12th-minute lead before Paddy Lane struck twice in a routine away victory for the new League One leaders. Here are our player ratings from Sixfields...
1. Max Thompson
Perhaps unfortunate to concede the corner which led to Pompey's first but didn't need to come flying off his line when they doubled their advantage - it made Lane's finish a lot easier than it should have been... 5.5 Photo: Pete Norton
2. Aaron McGowan
Among Town's stronger performers. Got his body in the way when making two or three important first half blocks and kept trying to drive the team forward even after the game had drifted away... 7 Photo: Pete Norton
3. Jordan Willis
Got lucky when he lost possession and Yengi hit the bar but the first half proved a difficult one for Town's defence and he paid the price when withdrawn at half-time... 5 Photo: Pete Norton
4. Sam Sherring
Raggett seemed to be his man for the opener. Wasn't aggressive enough as the Portsmouth man headed in on 12 minutes and Cobblers were unable to recover. He's enjoying a good season but this was one of his more challenging days... 5.5 Photo: Pete Norton