Saracens boss Mark McCall admitted Saints were just too clinical as his team bowed out of the LV= Cup at Franklin’s Gardens on Saturday.
Samoan centre George Pisi grabbed a hat-trick as Jim Mallinder’s men earned a 26-7 success to set up a final clash with Exeter Chiefs at Sandy Park on Sunday.
Saracens had dominated the first half, but only had seven points to show for it as Ben Spencer added the extras to Ben Ransom’s try.
And Saints got their act together in the second period, with Pisi shining bright in a ruthless display of attacking rugby.
“They were very clinical when they got into our 22, they came away with something every time and the game just got away from us a little bit,” said McCall.
“But I’m really proud of how we did in the first 50 minutes of the game in particular.
“We did some really good things and it was a really brave experience for our younger players.
“I thought Matt Hankin, our No.7, was outstanding today and it’s an important part of our younger players’ progression to play in games like this.
“Ben Ransom was exciting in that first 50 minutes and it was a great learning curve for him.
“Stephen Myler came off the bench and he was able to keep finding the corners, but all of our younger players did well.”