LuaLua, who has not started a competitive game since damaging an ankle in April last year, came off the bench to replace last week’s winning-goal hero Benjani Mwaruwari.

And he had been on the field less than 10 minutes when he picked up a pass from Sean Davis outside the area and took on Matt Holland before beating Scott Carson with a low drive into the far corner which the keeper will believe he should have saved.

But it was another deserved success for Harry Redknapp’s new-look side - although he did not include any of his deadline-day signings Andy Cole, Roudolphe Douala or Nikola Kranjcar.

An unchanged side had just too much for Charlton even though the London club made a cracking start and were unlucky not to break Pompey’s proud un blemished defensive record. They have not conceded in five games now.

Charlton manager Iain Dowie had to throw in on-loan South American Omar Pouso and promote Dennis Rommedahl and Marcus Bent from the substitutes’ bench after a crop of injuries diluted his squad.

Even so they made a shotgun start against Pompey’s much-vaunted defence with Marcus Bent outjumping Glen Johnson to head against the bar and Darren Bent hitting a post from the rebound as Sol Campbell and co waited in vain for the ball to go out of play.

But Pompey came back strongly and there were cries for a penalty from their fans behind the goal when Gary O’Neil’s cross – after the winger was sent away by Johnson’s clever pass – hit Amady Faye and bounced away for what referee Phil Down decided was a corner and not handball.

Talal El Kharkouri, Charlton’s centre-half, put the first of two first-half headers just wide following corners and Jimmy Floyd Hasselbaink forced David James to touch his shot behind for another flag kick.

Darren Bent shot straight at James before Benjani almost scored his third goal in four games with a cute header that fell just beyond a post when he connected with Johnson’s chip into the area.

Then Kanu had two chances which could have settled the game. First his shot, set up Benjani’s touch, required Scott Carson to make a full-length dive and save in the 24th minute.

Then the big Nigerian headed over the top when unchallenged at the far post from Johnson’s fine cross after the on-loan Chelsea ace worked his way around the back.

Both Bents had half chances for Charlton before the interval but the home side were happy to see Pedro Mendes’ meaty drive drift just wide at the other end after a sweet Portsmouth link between Johnson, O’Neil and the industrious Portuguese midfielder.

Charlton replaced Marcus Bent with centre-half Jon Fortune at the start of the second half and gave Faye his more familiar role in midfield against his old club.

But although the move – along with Holland’s arrival for the unhappy Pouso - gave the Addicks greater possession they rarely troubled the Pompey rearguard.

Hasselbaink’s long-range free-kick ballooned off the Pompey defensive wall for a corner and then Rommedahl, arriving on the end of a half-clearance, bulletted a shot inches wide.

But Charlton always looked vulnerable to a breakaway – and even more so when LuaLua replaced Benjani after 64 minutes.

He immediately tested Carson with a low drive and nine minutes later struck the vital goal after picking up a Davis pass outside the area.

The Cameroon international hit the ball well enough but Carson seemed slow going down for it and could only help the ball into the net.