It is not difficult – or time consuming – to list Pompey’s defeats this season.
Kenny Jackett’s side have been beaten just twice in League One, most recently by Charlton earlier this month.
Gillingham are the only other side to deny them any points, with a 2-0 victory at Fratton Park back in October.
Pompey head to Priestfield in search of a better result on Boxing Day, but Jackett does not have revenge on his mind.
The Blues boss said: “We don’t underestimate – or overestimate – anyone and always think that if we get our game right, we can collect points.
“There have already been two previous meetings with Gillingham this season, with the fixture in the Checkatrade Trophy, so both sides know a bit about each other.
"We don’t underestimate – or overestimate – anyone and always think that if we get our game right, we can collect points."
“We know it will be tough and well done to them for beating us in the league match at Fratton Park, but it’s a different game on Boxing Day.
“This is a key period with two fixtures on the road in quick succession and we have to make sure that everyone’s ready.”
Pompey currently sit proudly at the third tier summit and are the first team in the top four divisions to reach 50 points.
Jackett said: “The attitude of the players has been very good – we’ve had a settled side and the guys behind them have backed them up.
“We feel that there’s good competition to keep everyone on their toes and there has been consistency in our performances.
“You always just try to do as well as you can and I’ve been really pleased with our players – and pleased for them.
“They’ve all stuck together and we’ve been able to build a fantastic team spirit, which is a big thing at any club.”