A late drop goal from Ryan Lamb helped the home side to their 24-17 win at Franklin's Gardens.
Sale scored the only try of the game through Mark Cueto but indiscipline, which included losing two men to the sin-bin, ultimately cost them the match.
Director of rugby Mallinder accepted that his side were not at their best but the win was no less pleasing.
He said: "It was a workmanlike performance, with the rain beforehand making conditions difficult. Sale made it awkward for us by flying up to put us under pressure.
"We need to look after our ball better and then the gaps will come but we stuck at it and got the win."
Last week Northampton lost narrowly at Gloucester when Lamb missed a couple of crucial kicks, and as a result Myler was recalled for a starting berth.
Mallinder said: "We decided to go with Stephen Myler this week. He is an outstanding goal-kicker and is an excellent kicker out of the hand and it paid dividends today."
Tony Hanks, his Sale counterpart, was frustrated by the defeat and critical of referee Greg Garner.
Hanks said: "I am disappointed that we didn't come out of this game with a win. It is a very difficult place to come, for Northampton are a good side and a really good benchmark.
"Not many sides will come here and pick up a bonus point but I don't like losing and we are not one of those sides who come away and are happy just to lose with a bonus point picked up."
On his side's discipline, Hanks said: "We have no complaints about the yellow cards (Andrew Sheridan for killing the ball and Sam Tuitupou for a high tackle) but the referee (Greg Garner) was inconsistent and we felt that yellow cards should have been awarded against them at certain stages."
Hanks also considered that his side should have made more of their attacking chances and said: "Towards the end of the game I was disappointed that we didn't keep the ball in hand, but our youngsters wrongly took the safe option and kicked the ball away.
"We have come a long way since the beginning of the season and I want us to continue to play with the same attitude and energy and we will give anyone a game."
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