Goals from Reeco Hackett, George Hirst, Aiden O’Brien and Sean Raggett meant Rovers suffered a 4-0 defeat at Fratton Park in Sky Bet League One.
Rovers created the better chances in the first half but failed to capitalise. Joe Dodoo went the closest in the opening period when his shot from close range beat the keeper but was cleared off the line by Raggett.
It took two good saves from Gavin Bazunu early in the second half to deny first Josh Martin and then Tommy Rowe, but Portsmouth clicked into gear on the hour mark. Hackett headed in from close range to put them ahead and four minutes later, Hirst took the game away from Rovers with a cool finish underneath the onrushing Jonathan Mitchell. O’Brien made it three with ten minutes remaining and Raggett - having done his job at one end - headed in a fourth with the last touch of the match.
Gary McSheffrey made three changes to his side that were edged out in midweek by Ipswich Town. Dan Gardner, Joseph Dodoo and Kyle Knoyle were all handed starts with Ro-Shaun Williams and Mipo Odubeko named among the substitutes.
The home side also made three changes with Marcus Harness, Reeco Hackett and Clark Robertson included in the starting XI after missing out in Pompey’s midweek victory over Burton Albion.
Rovers created the majority of the early chances. Dodoo shot wide, before Joseph Olowu was inches away from connecting with Josh Martin’s corner-kick delivery. Gardner volleyed off-target, and some quick thinking almost set Tommy Rowe away, but the Rovers skipper was thwarted by the assistant’s flag.
Rovers went close on the 12th minute when another Martin delivery - this time from a free-kick - drifted narrowly wide of the far post without anyone there to tap it in.
Despite this, it was an important header from Ollie Younger to deny Ronan Curtis’ header and Kyle Knoyle defended well when Hackett attempted to get to the by-line.
The first shot on target for either team came in the 17th minute. Good footwork from Martin bought him a yard of space about 20 yards out - but the shot was straight at Bazunu in the Portsmouth goal.
And Bazunu was called upon again three minutes later - this time it was Reo Griffiths who stung the palms of the Manchester City loanee. The keeper spilled the first shot but managed to recover to deny Smith who had chased down the loose ball.
Rovers created the best chance of the period just before the half-hour mark. Griffiths and Smith linked up to find Rowe who demonstrated fantastic vision to pick out Dodoo in the six yard box. The striker’s effort beat Bazunu but brought an outstanding goal line clearance from Sean Raggett.
For Portsmouth a George Hirst header, and two under hit efforts from Michael Jacobs which drew stops from Jonathan Mitchell were the closest they came in the first half though crosses flashed across the Rovers box were a sign of the danger the wide men possessed.
Rovers had two good chances early in the second half. Smart counter-attacking play down the left saw first Martin and then Rowe force Bazunu into good saves at his near post.
Portsmouth took the lead just before the hour mark and doubled it four minutes later.
A cross from the right was met by the head of Hackett who headed beyond Mitchell from close range before Hirst capitalised on a misplaced header at the back to create a one-on-one which he slotted under the Rovers keeper.
Jacobs was next to go close for the home side when he curled an effort on target bringing a good stop from Mitchell. At the other end, substitute Kieran Agard was inches from connected with a through ball and Gardner’s chipped ball over the top had just too much pace on it for Griffiths.
The game became wide open with around 20 minutes as McSheffrey threw on more attacking options. Rovers went a bit more direct, but the experienced Pompey defence was stepping up at the right time to catch the forwards offside. Rovers went forward in numbers which left them a little exposed at the back and Mitchell made a couple of saves.
Aiden O’Brien made it 3-0 with his first touch of the match after coming off the bench in the 80th minute while Raggett headed in a fourth with the last touch of the match.