Saturday's 26-17 win over Harlequins has lifted Saints up to third, but they are just two points clear of fifth-placed Leicester.
Mallinder's men take on Newcastle – just a point further back in sixth place – at Kingston Park next and the Falcons
are buoyant after beating high-flying London Irish.
"Saturday's win was important," said Mallinder. "The top four is where we want to be and the next two weeks are going to be really important.
"We go to Newcastle, which is never an easy place to play at, and then we have Bath at home. They are games we can win, but we are going to have to play well to win both."
Saints are gunning for their first crack at the Premiership play-offs since 2004 when they lost 57-20 to Wasps at Adams Park under Wayne Smith.
Mallinder is moulding a potent side though, that could break a five-year barren run that has included relegation.
And he has probably the most devastating back three in the Premiership at the moment at his disposal in Bruce Reihana, Chris Ashton and Ben Foden.
Mallinder added: "The back three are playing well. We have got three good players there, but they are only good players if the other 12 inside them are working hard and giving them opportunities."
And as Saints prepare for Friday night's tough clash with Newcastle, Mallinder will have a virtually full-strength squad to choose from with Shane Geraghty and Dylan Hartley back from international duty and Euan Murray now playing after missing the first three months of the season through injury.
Mallinder said: "I was impressed at having Courtney Lawes and Ben Foden back on Saturday and Euan Murray back from injury, to see those lads playing well for us, that is what gets me going."
Murray came off the bench on Saturday after breaking his shin and damaging ankle ligaments on the British & Irish Lions tour in the summer.
"Euan has been out a long time, so to come back is a big thing," said Mallinder.
"It is going to take him a little bit of time to get back into things and to get real match fitness. He has been training for the past two weeks and he will only get better."
