A late goal from Reece James ensured that Doncaster beat Pompey 1-0 to continue their impressive record at Fratton Park.
The hosts improved after an insipid opening 45 minutes, but never really found any kind of attacking fluency.
And Rovers took advantage in the closing stages, with James curling a shot into the net to secure all three points.
Kenny Jackett made a couple of changes from the side that beat MK Dons on home soil the previous week.
Ben Close was handed a first league start of the season, with Andy Cannon also returning, as Bryn Morris and Michael Jacobs dropped to the bench.
The visitors started brightly on the sunny south coast and Craig MacGillivray came off his line on a couple of occasions.
One of them resulted in a key save to deny Fejiri Okenabirhie after the striker had raced onto Madger Gomes’ threaded pass.
But the Blues soon settled and enjoyed more possession, without really looking like doing much with it.
In fact, clear-cut chances were proving extremely hard to come by at both ends of the pitch in a largely lethargic contest.
Pompey did go close on 26 minutes, however, when Lee Brown delivered a corner towards Jack Whatmough at the far post.
The centre-back headed the ball down into the ground and Josef Bursik was able to parry it behind for a corner.
Ellis Harrison was working hard as a lone frontman, but was not being given enough support by his fellow attacking players.
There was a scare when Tom Anderson flung himself at James Coppinger’s free-kick and sent the ball into the side netting.
The defender’s momentum took him over the advertising hoardings and into the Fratton End, although thankfully he emerged unscathed.
Pompey did finish the first half with a flourish, though, and sent plenty of dangerous deliveries into the box that Doncaster did well to deal with.
Half Time: Pompey 0 Doncaster 0
The hosts were quickly out of the blocks following the restart and Bursik flapped nervously at a corner before Cannon fired a shot over the bar.
And they almost broke the deadlock on 53 minutes, with Harrison glancing Callum Johnson’s delivery inches past the post.
A Tom Naylor slip then provided an opening at the other end, with Coppinger finding Okenabirhie, whose shot was deflected wide.
MacGillivray soon had to beat away another effort from the striker before Brown did well with the mopping up.
Jackett made his first change just before the hour mark, with Ronan Curtis making way to be replaced by Jacobs.
And he was soon forced to make another one, as Harrison was hurt in a collision and Maquis was given the call to feature against his former club.
Pompey had looked the more dangerous side since the interval, although Marcus Harness could not force his shot home from a tight angle.
And when the ball sat up nicely for Cannon, he sent a sweet long-range strike fizzing just the wrong side of the post.
But it was Rovers who took the lead on 79 minutes, as James was left in far too much space to collect a pass from Josh Sims and curl home a neat finish.
Ryan Williams quickly came on for Close, as the Blues looked to find a route back into the contest by adding another player to their forward line.
And Bursik did well to deny Marquis an equaliser, adjusting his feet when the ex-Rovers frontman’s shot took a big deflection.
Pompey (4-2-3-1): MacGillivray; Johnson, Whatmough, Raggett, Brown; Naylor (c), Close (Williams 81); Harness, Cannon, Curtis (Jacobs 59); Harrison (Marquis 62)
Subs not used: Bass, Nicolaisen, Pring, Morris
Doncaster (4-2-3-1): Bursik; Halliday, Wright, Anderson, John; Whiteman (c), Gomes; Taylor (Sims 63), Coppinger (Richards 63), James; Okenabirhie (Smith 90)
Goals: James 79
Booked: James, Wright, Gomes
Subs not used: Jones, Butler, Williams, Lokilo
Referee: Brett Huxtable