Town completed a league 'double' over Portsmouth, thanks to Michael Chopra's first-half winner at Fratton Park.
It also represented a third consecutive win for Blues, following the victories over West Ham and Coventry.
Chopra's goal came after 12 minutes, with the striker reacting quickest to Daryl Murphy's header that had rebounded back off the post.
Paul Jewell made one change to the Town side, with Damien Delaney replacing the injured Ibrahima Sonko.
Carlos Edwards captained the side in the defenders absence, while Jack Ainsley earned a recall to the bench.
Town made a very bright start to the game and Delaney thought he had opened the scoring for Blues after just six minutes, but the defender saw his header come back off the bar after rising highest in the box to meet Andy Drury's delivery.
A minute later and the inform Emmanuel-Thomas tried his luck from fully thirty yards, which stung the palms of 'keeper Stephen Henderson before he gathered the ball at the second attempt.
Town were dominating proceedings and Michael Chopra was denied by Henderson after nine minutes, with his curling right-footed effort smothered well by the Pompey 'keeper.
But Town's dominance did soon pay off as Blues took the lead after 13 minutes. Emmanuel-Thomas saw a shot deflect to Daryl Murphy, who headed against the inside of the post, but fortunately Chopra was on hand to smash in the rebound from close range.
The hosts did respond well to going a goal behind, with striker Marko Futacs seeing a close range shot deflected over by a last-ditch block from Tommy Smith after 25 minutes. The striker then headed over from the resulting corner after climbing above his marker.
Portsmouth were pressing for an equaliser and Erik Huseklepp was denied by Arran Lee-Barrett, who dived low to his right to keep out the shot with ten minutes remaining of the first-half.
But Town were still creating chances of their own and Drury was unlucky with a long-range drive a minute later, that flew just wide of Henderson's right-hand post.
Drury went close again for Town with four minutes remaining until half-time, with the midfielder latching onto a Lee Martin pass following a superb flowing move from Blues, only to see his shot parried away from goal by Henderson.
As the half moved into injury time, Town went close again. Good work from Aaron Cresswell saw him work some space on the left to cross, where Chopra was waiting but was unable to add the decisive touch to score his and Town's second and the two sides went in goalless at the break.
The second half turned into quite a scrappy affair and the first chance of the half didn't arrive until the 62nd minute, with Pompey striker Futacs firing over after turning in the box.
Town responded seconds later, with Smith seeing a goalbound header cleared off the line by Ben Haim following a Drury corner.
The hosts missed a great chance to draw level after 64 minutes, with substitute Dave Kitson firing wide after good work from Kelvin Etuhu on the right-hand side.
By now the game had opened up and Martin had a chance to extend Town's lead after being played in by Murphy, but the midfielder failed to keep his shot down from inside the area and the ball sailed high over Henderson's bar.
Two minutes later and Emmanuel-Thomas fed the onrushing Drury with a defence-splitting pass, but the midfielder failed to hit the target under pressure from Jason Pearce.
The hosts then thought they had drawn level after 72 minutes, with Town failing to clear a Greg Halford throw-in, but Kitson was alleged to have fouled Lee-Barrett in the build up and the referee disallowed the goal.
Town were still looking dangerous on the break and Martin came within a whisker of doubling the lead with 14 minutes remaining, but his shot came back off the post with Henderson well beaten.
As the game reached its final stages, Pompey almost drew level through Ben Haim, but the former Chelsea defender saw his cross flash right across the face of Lee-Barrett's goal.
The hosts continued to press for an equaliser but Town held firm to claim all three points with a solid performance.
Town are next in action on Saturday, welcoming Cardiff to Portman Road, in search of a fourth successive victory.
Portsmouth: Henderson, Halford (Webster 90), Rocha, Pearce, Ben Haim, Ward, Lawrence (Kitson 44), Mullins, Etuhu (Benjani 79), Futacs, Huseklepp. Subs not used: Ashdown, Mokoena.
Booked: Ben Haim, Halford, Rocha
Town: Lee-Barrett, Edwards, Delaney, Smith, Cresswell, Drury, Hyam, Martin, Emmanuel-Thomas, Murphy, Chopra (Scotland 79). Subs not used: McCarthy, Ainsley, Bullard, Leadbitter.
Booked: Hyam, Emmanuel-Thomas, Delaney, Scotland