Goal-shy Pompey’s miserable run continued in a 1-0 loss to Doncaster - their sixth straight defeat.
Former target Iain Hulme scored the decisive goal in the 24th minute after abject defending from Guy Whittingham’s men.
A mix-up between Brian Howard and Mikkel Andersen let the striker in to net at the near post – and it proved to be the match-winner.
Pompey gave debuts to Nathaniel Mendez-Laing and Paul Benson, the former impressing tremendously in a wide role.
However, the attacking duo couldn’t help prevent another loss, in the process stretching it to 488 minutes since the Blues netted a goal.
Lubomir Michalik came closest with a 75th-minute header which struck the crossbar, while Izale McLeod wasted a one-on-one following a glorious Howard pass.
Yet, despite an improved second-half display, Pompey slipped to 19th in League One.
Mendez-Laing and Benson were the only changes to the side which suffered defeat at Bury last weekend.
That meant Ashley Harris and Jon Harley dropping to the bench, while Akos Buzsaky was again missing from the squad.
When the match got under way, it was Izale McLeod who would have Pompey’s first attempt on goal, swivelling round to drill in a shot which trickled wide in the seventh minute.
At the other end, a free-kick was touched to Martin Woods, who crashed in a shot from distance which had Andersen pushing it over the bar.
A marvellous move from the Blues on the 20th minute saw Andersen throw the ball out to Mendez-Laing and he surged through the heart of the Doncaster defence.
The winger then slipped through a superb reverse pass with was collected by McLeod on the left-hand side of the box, yet the striker could only shoot the wrong side of the near post.
It was the visitors, however, who took the lead in the 24th minute.
Mustapha Dumbuya failed to get the ball clear and when Martin Woods capitalised he crossed from the left and Hume slid home a goal while Andersen and Howard stood still waiting for the other to intervene.
The response was immediate, McLeod’s cross from the left half-volleyed by Williamson and taking a wicked deflection off a defender’s head to ricochet just past the post.
Paul Keegan the gave possession away on the edge of the area and Russell drilled in a first-time shot with Woods held comfortably.
The half ended with the impressive Mendez-Laing striking a ferocious shot from 25-yards out narrowly over the bar.
Pompey picked up after the break and in the 56th minute had the ball in the back of the net from Williamson, only to be ruled out of off-side earlier in the move.
Andersen kept the scoreline down, though, in the 69th minute when he pushed the unmarked Rob Jones’ header past the post after David Cotterill’s corner.
Regardless, it was better from the hosts after the break and in the 75th minute substitute Harris’ corner was headed against the bar by Michalik.
A stunning pass from Howard then released McLeod through the middle but the striker’s attempt to clip it over the on-rushing keeper also saw it clear the bar.
It was a glaring miss and one the hosts were left to rue as the equaliser would not arrive and a sixth defeat in a row ensued.
Doncaster 1 (Hume 25)
Pompey: Andersen, Dumbuya, Gyepes, Michalik, Dickinson (Compton 83), Williamson (Harris 71), Russell, Howard, Mendez-Laing, Benson, McLeod. Subs: Eastwood, Harley, Walker, Ertl, Webster.
Doncaster: G Woods, Griffin, Husband, Jones, Harper, Keegan, M Woods, Paynter (Brown 75), Cotterill (Syers 82), Spurr, Hume (Martis 87). Subs: Maxted, Blake, M Woods, Ball.
Referee: Iain Williamson (Berkshire).