Pompey were fortunate to go in at the break just one goal behind.
So the 1,966 travelling supporters would surely have left the DW Stadium happy to see their side snatch a point against Wigan.
Ivan Toney gave the Latics an early lead and they also hit the woodwork on three occasions, while Luke McGee made a string of fine saves.
But Chey Dunkley’s red card for lashing out at Brett Pitman gave the hosts hope and Conor Chaplin came off the bench to head a leveller.
Gareth Evans was also dismissed late on for a second bookable offence, but the game ended all squad and Kenny Jackett was satisfied with the outcome.
The Blues boss said: “It was a very good point for us because if you finish above Wigan this season, you’ll probably get automatic promotion.
“They’re strong in every position and take some stopping. But our keeper was outstanding and contributed to a decent result. He kept us in it with some fine saves.
"We don’t want to just be a League One team, but there’s definitely some way for us to go yet."
“I’ve got to say that it was an excellent header from Conor because he still had quite a bit to do when the ball came across.
“Ben Close also had a really good second half when he came on. He’s been looking for a chance and I was pleased with him.
“There are some good young players coming through, and Close and Chaplin were big pluses after coming through our academy.
“They’ve now got to take those chances that they’re going to get and try to turn Pompey into a force in this division.
“We don’t want to just be a League One team, but there’s definitely some way for us to go yet.”
The dismissals for Dunkley and Evans mean that there have already been four red cards in matches involving Pompey this season.
Jackett said: “We’ve had lots of incidents like those – and there was a challenge on Adam May in our previous game that could have been a sending off.
“The referee was a lot closer to the first one than me and it all depends on his interpretation of what happens.
“Gareth’s was definitely a foul, but it was it a booking? I’m not sure, but we just have to accept it and move on.”