Adam McGurk kept up Pompey’s unbeaten record with a spectacular second-half strike at Oxford United.
McGurk’s piece of opportunism from 35 yards earned the 10-man Blues a 1-1 draw at the Kassam Stadium.
His 61st-minute effort cancelled out Liam Sercombe’s first-half opener against Michael Appleton’s side.
Pompey had Paul Jones to thank for two important first-half saves as he came in for the injured Brian Murphy.
Paul Cook’s side started the game the better of the two sides with their 4-2-3-1 formation causing the home team problems.
The only half-chance they had was when Christian Burgess headed wide from a corner after 11 minutes.
The home side came back into the match as the half wore on, however, with Danny Hylton leaving Matt Clarke for dead after 27 minutes - but Jones saved well.
Conor Chaplin was forced off three minutes later with an injury and was replaced by Matt Tubbs.
The home side took the lead after 33 minutes with Sercombe firing home from the edge of the box, as Pompey failed to clear their lines.
Ben Davies replied by firing a free-kick just wide five minutes later.
But it was the U’s who were on top and pushing for a second as Kemar Roofe prodded the dangerous Callum O’Dowda’s cross wide.
Oxford should have had a second in stoppage time as Clarke missed the ball and Roofe went clear - but Jones won their one-on-one duel.
The ineffective Nigel Atangana was withdrawn for Adam Barton at the break.
Pompey started brightly after the break with a flowing move ending with Slocombe gathering Evans’ cross.
McGurk then headed another Evans cross over before taking centre stage after 61 minutes.
The attacker delivered a goal out of nothing as he picked up the ball 35 yards out and struck an early shot from 35 yards which caught Slocombe off guard.
It was a goal out of nothing but gave Pompey the platform for a period of dominance.
Jones did have to be alert to keep out Mullins’ header but it was the visitors dominating possession.
That changed when Doyle was sent off with nine minutes left for a second yellow card after blocking Sercombe.
It made for a nervy finale for the visitors - but Pompey held on to pick up an important point.