Lamb, a summer recruit from London Irish, helped create first-half tries for James Downey and Paul Diggin, and went on to end with a haul of 16 points as he booted two conversions and four penalties.
Wing Scott Armstrong went on to complete the scoring late on with Saints' third try, and while Mallinder was pleased with the overall display, he reserved special praise for Lamb.
But he stopped short of saying the performance had made the former Gloucester man his number one fly-half ahead of Stephen Myler.
He told ESPN: "We said we are a good team and we can play well and we proved that today.
"We played some good rugby, our defence was good last week and this week it was outstanding so I am really pleased with the performance."
Of Lamb, he added: "Ryan played really well, he was fantastic and took some good options to get us on the front foot, but we have two fly-halves and that's what you need to be successful and I am really pleased for Ryan Lamb today.
"It's how we want to play the game and how it should be played, and if you put the opposition under pressure you have a good chance of coming out with a win."
Lamb himself was just pleased to see Saints end their disappointing run.
"We know we can play, we are a good side," he said. "We have lost games by narrow margins and we want to prove what we can do. We are a fantastic attacking side with top players across the board so it is good to get the monkey off our back.
"Externally there is always pressure, but in house the boys are confident in what we can do and we knew the performance was in us. We have a lot of new signings but when it gels together it comes out like that.
"Our forwards were fantastic, they gave us go-forward ball and that makes it easier for us."
But Lamb would not be drawn on whether he had done enough to usurp Myler in the number 10 pecking order.
"Steven is a fantastic player and with the Premiership as it is you need a big squad," he said.
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