Gareth Evans could have wilted under the disappointment of seeing his first half penalty saved.
Instead the miss motivated him to score the opening goal of a convincing 4-1 victory over Oxford at Fratton Park.
He slotted into the net within three minutes of the restart, having earlier watched his spot-kick saved by Jonathan Mitchell low to the keeper's left.
That saw the floodgates open, with Rob Dickie adding an own-goal and Jamal Lowe bagging a brace, including a stunning stoppage-time strike.
Evans said: “I normally go that way and don’t know whether they had done their homework, but I probably could have put it further in the corner.
“People miss penalties and it was a decent save, so it’s just one of those things really and it’s important not to let your head drop.
“You don’t know what’s going to happen for the rest of the game, so you just need to stay confident and I ended up scoring anyway.
"It’s just one of those things really and it’s important not to let your head drop."
“I was obviously keen to make up for the mistake and was luckily able to cancel that out, which isn’t always the case.
“We dominated the game from the first minute and, once again, it was an improved performance from the previous week.
“There was always confidence that the goals were going to come because we were on top and unlucky not to be in the lead at half-time.
“We should have taken a few of our chances, but we kept the right mentality and thankfully ended up with the three points.
“Once it got to 3-0 we did take our foot off the gas a bit and invited them on to us, which is something we’ll look to rectify if we get into that situation again.”
Pompey and Peterborough are the only League One sides with a 100 per cent record so far, but Evans is not getting carried away.
He said: “It’s a good start, but it is still early days. We’re not going to get too high because you don’t know what’s around the corner.
“We’ll just take positives from the performance and look to keep the run going at Bristol Rovers on Tuesday.”