Results at the weekend saw Pompey drop to 11th spot in the League One standings.
So Reeco Hackett knows how important victory against Charlton is on Monday night to keep play-off hopes alive.
The Blues have as many as three games in hand on the sides above them in the table and are looking to narrow an 11-point gap to Oxford in sixth.
Their next opponents, meanwhile, are even further behind in 15th position and Hackett is aware that his side have to get their season back on track.
He said: “Off the back of a disappointing result at Sunderland, we’ll be looking to get straight out there again and collect all three points.
“We started really well in that game and then it was just a mistake that led to their goal, which also happened against MK Dons.
"We’ve got the targets that we set ourselves at the start of the season and we need to start winning again if we want to achieve them."
“So we need to cut out those errors and then look to improve our overall performances in the second half.
“It’s going to be a big game on Monday night between two sides who are looking to climb the League One table.
“The clubs are both outside the play-off places at the moment and we want to start closing that gap again.
“We’ve got the targets that we set ourselves at the start of the season and we need to start winning again if we want to achieve them.”
Hackett made 24 appearances for Charlton at the start of his professional career, which included an EFL Trophy outing against his current club.
He said: “I had a good few years there and still know a few of the boys, as well as (manager) Johnnie Jackson and (assistant) Jason Euell.
“It will be good to see them again, but my focus is on trying to get out there and helping Pompey get a win.”