Ronan Curtis continued his run of fine form by bagging a brace to help secure all three points for Pompey against Rochdale.
Ryan Williams was also on target at Spotland, as the Blues displayed a clinical edge that has been lacking at times this season.
The hosts saw plenty of the ball, but did not do much to threaten their visitors, while Curtis made the most of dangerous deliveries from John Marquis and Williams either side of the break.
And after chances to wrap the victory up had been spurned, Williams opened his Pompey account to settle any nerves.
Kenny Jackett made three changes from the side that won at Harrogate Town to progress in the FA Cup.
Skipper Tom Naylor and Sean Raggett were injured in that game, with Anton Walkes and a fit-again Oli Hawkins replacing them.
Gareth Evans dropped to the bench to make way for Ellis Harrison, while Lee Brown wore the captain’s armband.
The hosts looked lively and dominated possession in the early stages, with Jimmy Keohane curling a shot past the post.
Matty Done was looking particularly dangerous whenever he burst forward, but Dale were not making the most of his trickery.
And the Blues started to feel their way into the contest, although Brandon Haunstrup will want to forget a free-kick that not only cleared the bar, but flew out of the ground.
Pompey did have the lead on 15 minutes, though, and it was largely thanks to the good work of Marquis.
He collected a pass from Williams and spun beautifully on the ball before cutting it back for CURTIS to fire home.
Some dangerous deliveries from Haunstrup and Williams caused problems, as the visitors tried to build on their advantage.
Rochdale began to take charge of possession once more, although they were not doing much to test Craig MacGillivray.
And the Blues almost snatched a second goal on 37 minutes, with Hawkins’ header from a corner blocked and nobody able to force home the loose ball.
Their opponents had one excellent chance to level before the break, as Rekeil Pyke glanced Keohane’s cross against the post.
Half Time: Rochdale 0 Pompey 1
Keohane tried his luck from long-range seconds after the restart, with the ball flying high over the bar.
But the Blues were more clinical when they went up the other end moments later and a low Williams delivery was slammed home by CURTIS.
Jackett wanted his men to build on that, screaming at them from the sidelines to keep pressing and make life uncomfortable for their opponents.
A poor clearance from Dale keeper Robert Sanchez flew straight to Williams just before the hour mark, but it caught the winger by surprise and he was unable to capitalise.
The hosts were still being frustrated and when Callum Camps finally did get a shot on target, MacGillivray flew to his right to make a fine save.
The Scotland international then dusted himself down to commandingly claim the resulting corner, drawing cheers of approval from the noisy travelling army.
Pompey were doing their best to keep hold of the ball and slow the game down, while still looking capable of adding to their lead.
When Harrison was bundled to the turf on the right, Haunstrup’s free-kick was nodded against the bar by Hawkins.
Then, seconds later, Curtis burst forward with lightning pace and slotted the ball across for Williams, but Sanchez was quickly off his line to deny the winger.
Jackett soon made a change, with the hard-working Harrison trudging from the turf and replaced by Brett Pitman.
Rochdale were doing their best to try to reduce the deficit, but the Blues were resolute at the back and a real menace on the break.
And they finally made sure of the points late on, with Pitman unselfishly passing to the unmarked WILLIAMS, who coolly slotted home.
Rochdale (4-1-2-1-2): Sanchez; Matheson, O’Connell, Norrington-Davies, Keohane (Tavares 77); Williams; Done (Bradley 83), Morley (Hopper 87); Camps; Henderson (c), Pyke
Subs not used: Lynch, Dunne, Brierley, Gillam
Pompey (4-2-3-1): MacGillivray; Haunstrup, Hawkins, Burgess, Brown (c); Walkes, Close; Williams, Marquis, Curtis (Harness 90+1); Harrison (Pitman 75)
Goals: Curtis 15, 47, Williams 88
Subs not used: Bass, Bolton, Downing, Cannon, Evans
Referee: James Adcock
Attendance: 3,789 (993 Pompey fans)