Pompey moved level on points with Sunderland in the race for League One automatic promotion after cruising to a 4-1 win over relegation-threatened Rochdale.
The Blues made it five straight victories to continue their momentum in the final sprint for the top two.
First-half goals from Oli Hawkins and Brett Pitman's penalty were followed by substitute Gareth Evans and Jamal Lowe netting after the restart.
That took fourth-placed Pompey on to 80 points – the same number as Sunderland, in third, after they were beaten 5-4 at home by Coventry.
Meanwhile, the gap to the automatic promotion places and second-placed Barnsley remains two points after they beat Fleetwood, although the Blues have a game in hand.
The Blues were quick out of the traps and were rewarded with an opener on 21 minutes.
Hawkins' superb glancing header from Lowe's cross at the near post gave Dale stopper Josh Lillis no chance.
Lowe then wasted a great opportunity to double Pompey's advantage two minutes later. Smart work from the winger sent him racing away but his effort was kept out by Lillis.
Rochdale were looking dangerous on the counter, with the Blues fortunate not to let them back in on 24 minutes.
Christian Burgess' underhit back-pass put goalkeeper Craig MacGillivray in trouble. But the Scot's clearance cannoned off Aaron Wilbraham and went wide.
Pompey were then gifted the chance to double their advantage a minute before the break.
Rochdale defender Ethan Ebanks-Lendell wiped out Nathan Thompson just inside the area, with a penalty awarded.
Pitman kept his composure, sending Lillis the wrong way to add a deserved second.
Dale were the brighter early in the second period and grabbed a lifeline on 54 minutes.
Sloppy Pompey defending saw Wilbraham left in acres of space following a quick counter-attack, with the forward slotting past the onrushing MacGillivray.
That strike seemed to spark life back into the Blues and they came agonisingly close to restoring their two-goal advantage two minutes later.
Burgess headed Brown's corner back across goal, yet Dale somehow managed to hack the ball away off the line.
But Pompey's pressure paid off on 62 minutes as they added a third.
Lowe was again the provider. floating in a cross for substitute Evans to head home just five minutes after his introduction.
Rochdale enjoyed a spell of possession and sustained pressure following the Blues' third goal.
However, Lowe capped an inspired display to wrap up the victory for Kenny Jackett's troops 11 minutes from time.
The winger latched on to Matt Clarke's pass, raced away before rounding Lillis and firing home.