Cameron Burgess’s second goal of the season for the Blues levelled Marlon Pack’s opener for Portsmouth to leave the scoreline 1-1 at half-time.
Town named an unchanged side, despite boss Kieran McKenna having said in the lead-up to the match that two players had been unwell prior to the 3-0 Boxing Day home win against Oxford and another seven had subsequently reported symptoms.
Conor Chaplin and Marcus Harness started against their old club but Town’s third former Pompey player Gassan Ahadme travelled but along with Richard Keogh and Kane Vincent-Young wasn’t included in the 18.
Portsmouth, who had also had illness worries, made four changes from the 0-0 draw at Exeter on Monday with Ipswich-born Joe Morrell, Zak Swanson, Josh Koroma and Connor Ogilvie coming into the side for on-loan Blues striker Joe Pigott, who was ineligible, and former Town loanee Ryan Tunnicliffe, Denver Hume and Reeco Hackett, who all dropped to the bench.
The Blues made a scruffy giving the ball away on the edge of their own area before the hosts took the lead in the fourth minute via the game’s first shot.
Skipper Sam Morsy was harshly penalised for a foul on Koroma five yards outside the area and Pack struck a free-kick beyond Christian Walton to his left and into the net off the inside of the post.
Having conceded their first league goal in the opening 15 minutes this season, Town quickly began to dominate play but with Portsmouth looking to give them little time on the ball.
And the Pompey lead lasted only seven minutes. Pack fouled Morsy on the right, Lee Evans whipped over a free-kick from the right and Burgess, for the first time without his mask since undergoing facial surgery, turned the ball into the net from five yards.
Having got back on terms, Town maintained their superiority, however, in the 16th minute goalscorer Burgess was shown the game’s first yellow card for a foul on Owen Dale.
There was a scare for the Blues in the 18th minute when a corner was diverted out to Koroma just outside the area to the left from where the winger struck a shot which Woolfenden cleared from in front of the line.
But Town were still in control and in the 22nd minute Evans struck a powerful shot from 25 yards which home keeper Josh Griffiths did well to save down to his right and hold onto with Freddie Ladapo sniffing around for a rebound having scored in similar circumstances on Monday.
The Blues continued to see most of the ball and on 35 Morsy hit a low effort from distance which Griffiths stopped to his right.
Town maintained their dominance, passing the ball around slickly and at pace and in the 44th minute should have gone in front. After a long spell of possession with Woolfenden having joined in the attack, Burns crossed low from the right and found Ladapo but the former Rotherham man was through his shot as the ball arrived and it looped into the stand.
The half-time whistle sounded with Town still on the ball and looking for another opening from which they might score a second goal, which their display would certainly have deserved.
The Blues had appeared unaffected by Pompey’s early goal and quickly got into their stride and grabbed the equaliser, yet another set-piece goal with Burgess taking his opportunity from an excellent Evans free-kick.
From there, Town dominated and created one or two openings without making Griffiths work too often, while Ladapo will have been disappointed to have snatched at his late chance.
Pompey had had the occasional opportunity but with Walton untested since Pack's goal and the Blues will be confident that if they maintain their level of performance in the second half the three points should be theirs.
Portsmouth: Griffiths, Morrison, Raggett, Robertson (c), Swanson, Morrell, Pack, Ogilvie, Dale, Bishop, Koroma. Subs: Oluwayemi, Hume, Tunnicliffe, Curtis, Hackett, Jacobs, Scarlett.
Town: Walton, Donacien, Woolfenden, Burgess, Burns, Evans, Morsy (c), Davis, Chaplin, Harness, Ladapo. Subs: Hladky, Edmundson, Leigh, Humphreys, Edwards, Aluko, Jackson. Sam Allison (Wiltshire).