Saints surged into the semi-finals of the Anglo-Welsh Cup as they hammered Harlequins 36-10 at Franklin's Gardens on Friday night.
Tries from George North, Tom Stephenson, Ahsee Tuala and Ken Pisi wrapped up the bonus point inside the opening 30 minutes.
And Pisi added his second score after the break, making it five tries in as many matches for the Samoan, as Saints cruised to victory.
Quins only had tries from Mark Lambert and Joe Marchant to shout about as they saw their 100 per cent record in the competition go up in smoke.
Saints will look forward to a semi-final in March, with their immediate attention now switching to the Aviva Premiership game at Bath next Friday.
They have won four of their five matches in all competitions in 2018 and will be full of confidence for their return to league action.
Saints certainly showed plenty of belief early on against Quins, being held up over the line on one occasion and denied a try by the TMO on another.
But it didn't take long before their lengthy spell on the Quins line paid off as North, released by Wales in a bid to get game time, found space on the left to score.
Piers Francis, making his return from concussion, landed the conversion and he was soon doing so again after a fine Saints score.
Jamie Gibson intercepted the ball on the edge of his own 22 and after he was brought to ground in the Quins half, possession moved quickly to Stephenson, who scored.
With the score 14-0 after just 14 minutes, it was already looking likely to be a long night for the away side.
It was wave after wave of Saints pressure, with North, Stephenson and Mike Haywood looking particularly lively in the formative stages of the game.
And after a slip in the Quins defence, Saints scored their third try with full-back Tuala sauntering in.
Francis again converted and the bonus-point score looked imminent.
So it proved as Stephenson and David Ribbans combined out wide and Pisi picked up to storm in for the score.
Francis missed the conversion, but the bonus point had been secured in ruthless fashion.
Saints showcased their defensive steel before the break, defending superbly to stop Quins, who were camped on the line.
But eventually the side from The Stoop broke through as prop Lambert made it over.
James Lang missed the conversion and Saints held a richly-deserved 26-5 lead at half-time.
And they extended their advantage early in the second period after Api Ratuniyarawa's break helped to earn a penalty, which Francis kicked.
The game then calmed down, with both teams ringing the changes ahead of the return to Premiership action next week.
Saints handed a debut to South African flanker Heinrich Brüssow, who came on with 18 minutes remaining, and Pisi scored his second try soon after.
Stephen Myler, on for Francis, added the easy extras, but Quins had the final say as Marchant slipped through a couple of attempted tackles to score.
Saints: Tuala (Foden 73); Pisi, Tuitavake, Stephenson, North; Francis (Myler 62), Reinach (Groom 56); van Wyk (Ma'afu 66), Haywood (Marshall 62), Brookes (Ford-Robinson 56); Ratuniyarawa (Brüssow 62), Day (c); Ribbans, Gibson, Harrison (Eadie 50).
Harlequins: Morris; R Chisholm, Marchant, Cheeseman, Alofa Alofa; Lang (Prior 70), Lewis (Kitto 51); Lambert, Gray (Piper 62), McNulty (Ibuanokpe 56); South, Horwill (Twomey 40); White, Wallace, J Chisholm (c) (Luamanu 62).
Referee: Nic Berry