With just 10 minutes of the first half remaining, it was as comfortable as Pompey had looked on their travels all season.
And yet they somehow found themselves trailing 2-0 to MK Dons at the break, going on to suffer a 3-1 defeat.
Goals from Rhys Healey, Conor McGrandles and Alex Gilbey did the damage, with Ronan Curtis grabbing a stoppage-time consolation.
It was a disappointing way to end 2019 and Kenny Jackett was rueing the fact his side failed to make the most of their early dominance.
The Blues boss said: “We had a lot of the game and looked particularly strong in the first half-hour, having the ball in and around their box.
“There were some good situations and a lot of corners, but we couldn’t make it happen or the ball wouldn’t fall for us or they defended well.
"You have to be able to dig in when you’re away from home and it was quite ragged from us in between their first two goals."
“We didn’t do enough to finish those opportunities we had. You need to score when you’re on top and we didn’t do that – that’s the important thing.
“We were in control and they went ahead against the run of play after capitalising on a mix-up between our defender and goalkeeper.
“MK Dons got a second, but I still thought we could come back into it in the second half because we had more chances.
“You have to be able to dig in when you’re away from home and it was quite ragged from us in between their first two goals.
“To be fair to MK Dons, they took those chances when they came along and defended their box very well for long periods of the game.”
With the transfer window about to reopen, Jackett knows there will be plenty of transfer rumours flying around.
He said: “We’ll be linked with a number of players with January around the corner because we’re a big club.
“I’m not going to say we won’t bring in one or two and our recruitment team are working hard to see what we can do.”