Pompey were left to rue a moment of defensive sloppiness as they fell to a 1-0 loss at Leeds.
Danny Pugh’s free header after 14 minutes was the difference between the two sides at Elland Road.
Pugh was given the freedom of the Pompey box to head past Stephen Henderson - who replaced Jamie Ashdown in goal.
Pompey looked like they were going to be taken apart by the home side as they spent the first half under the cosh.
Greg Halford’s header, which was superbly saved by Andrew Lonergan, was their only chance of note before the break.
But Steve Cotterill’s men roused themselves after the interval with Kanu entering the fray.
Cotterill again switched the formation, with Kanu joining Benjani up top, and the face of the match changed.
Pompey had much the better of the play but couldn’t get the equaliser they were pushing for.
Their best chance fell to David Norris, who was put clear by Liam Lawrence, but a heavy first touch saw the opportunity passed up.
Joel Ward also poked an effort just over with 15 minutes remaining, but it proved to be Leeds’ day.
The result leaves Pompey in 18th on nine points.