The South Coast club are one point and one place above the relegation zone and currently have 28 points from 27 games.
Three wins would give Pompey a total of 37 points, three points below what managers usually target as the tally which guarantees survival.
But Mullins, who signed from West Ham in January, is confident his new club can avoid relegation to the Championship.
"The squad we have here is a very strong and very healthy squad," he told The News.
"It is strong enough to get a few wins. Three wins will jump us right up the table and keep us there.
"If people drop a few points and we do that, things will be sorted. We focus on what we do. If we get our results it's in our hands.
"You do look at the teams around you and see which ones drop points. It's always a very interesting time.
"Everyone has an eye on that, but we know it is what we do on the pitch which counts. If we are doing well and we are on a roll we have to take that into each game.
"We believe we can get out of it."
RespondedFour points from a possible nine since Paul Hart stepped up to succeed Tony Adams until the end of the season at least has lifted spirits within the camp.
Mullins returned to the starting line-up for the narrow defeat by Chelsea last time out and he acknowledges that the squad have reacted positively to Hart and assistant manager Brian Kidd.
"The boys are responding. That's the main thing you want as a manager," he added.
"He has his ideas. If you can get people to respond, take on board your beliefs and then go out on to the pitch and carry them out you will be successful."
Pompey took full advantage of a rare free weekend off last week by enjoying a few days' warm weather training in Dubai ahead of their crucial clash with Middlesbrough on Saturday but Mullins insists he could not wait to get back.
"We need the points. If we're picking them up then that is good enough," he said.
"You almost want to get back to the daily grind. We want to play games and start picking up points.
"When you do have the weekend off you can sit back and relax, but I'm sure we'd rather be out there playing."