Alan Dickens praised his Saints players for showing what the club means to them in the sensational win at Welford Road on Saturday.
Tries from Ben Foden, Cobus Reinach and Ahsee Tuala, allied with 12 points from the boot of Stephen Myler, secured a 27-21 Aviva Premiership success at Leicester Tigers.
It was Saints' first win at Welford Road since February, 2007 and first league double against Leicester since the 2003/04 season.
It was a huge show of character after the previous week's 63-13 thrashing at the hands of Saracens and virtually guarantees Saints' safety in the Premiership.
And interim head coach Dickens said: "I am really proud and it's for the lads because a lot of people have questioned their attitudes and their commitment to the club.
"We've seen here what it means to them.
"If we had all night we could go through one to 23 and say how well the players played.
"They put their bodies on the line for 80 minutes and I can't praise them enough.
"I thought they were fantastic."
Rob Horne was made Saints captain for the first time, but he was forced off after just 12 seconds after being knocked unconscious in a collision with Sione Kalmafoni.
Horne was taken straight to hospital, but was later reported to be conscious and talking.
And Dickens paid tribute to the role the Australian centre had in the long-awaited victory at Leicester.
"I'm really disappointed for Rob Horne because he took the bull by the horns during the week, we asked him to be captain and he's led well throughout the week," Dickens said.
"The messages he's given the players is to pull together and perform as a team and he's been fantastic. We wish him well."
And Dickens added: "You saw at the end of the game, the emotion that came out and that's due to two things: winning at Welford Road, which doesn't come around very often, and the frustration of the season, which has ultimately been disappointing.
"I just didn't understand the difference between the two halves last week, but the attitude today was fantastic."