Northampton Saints bagged a first derby win of 2019 in emphatic fashion, by running in seven tries against Leicester Tigers at Franklin's Gardens to advance to the Premiership Rugby Cup semi-finals.
Cobus Reinach's second-half double helped the hosts pull away, after they led 19-10 at the break thanks to tries from James Grayson, James Fish and Dom Barrow.
And Saints kept Tigers at arm's length throughout the second 40, with Heinrich Brüssow securing the bonus point and then Tom Collins adding another try in the corner to Reinach's brace – as the men in Black, Green and Gold racked up their biggest margin of victory in the East Midlands derby since 1999.
Tigers drew first blood after a scrappy, hard-hitting opening period, as Fred Tuilagi bundled over from close range to hand his side an early 7-0 lead.
Saints had to work hard to find an opening after that, as the Leicester defence stood firm and trapped the home side in their own half before a well-placed kick by Grayson gave them a first taste of action in the Tigers 22.
Moments later, it was Grayson who struck with a mazy run down the right flank, scything through the Leicester line and scoring his side's opening try of the game – levelling the scoreline with his conversion from out wide.
Northampton had flipped the momentum and worked Tigers back to their try line again, bagging a lineout on the five metre and expertly setting up a driving maul to allow Fish to touch down at the back and put Saints 12-7 ahead.
The Saints pack then thwarted Leicester as they looked to come back into the contest, and a brilliant kick by George Furbank saw the game switch from one end to the other in the blink of an eye.
Leicester gave away a penalty, and with the advantage on their side Northampton quickly shifted the ball out wide for former Tiger Dom Barrow to score his first try in Black, Green and Gold against his former club in the left corner.
Joe Ford then had two shots at goal to reduce the gap, and was successful with one of two penalties to take the scoreline to 19-10.
Saints got the perfect start to the second half as Brüssow sealed the all-important bonus-point try as he barged his way through several Leicester tackles under the sticks.
The returning Tom Varndell looked to have scored for Leicester on his Premiership Rugby Cup debut, but remarkably Jamie Gibson managed to hold the ball up as they both slid across the whitewash, in what was a tricky period of play for Saints.
Leicester were piling the pressure on with the line at their mercy, but Northampton held firm and won a vital scrum penalty to clear their lines to the delight of the home crowd.
But out of nowhere Ford reduced the gap to just six points with an intercept score after 69 minutes, bursting 50 metres up the field for Tigers' second try of the afternoon.
However, Saints kept their cool and after working their way back into the Leicester 22, Reinach flew off the back of a ruck and burrowed his way through a gap to put the result beyond doubt.
Tom Collins did not want to stop there however, and left the visitors' defence for dust on the left wing for him to cross for a sixth try in the corner, before Reinach rounded off proceedings with a sensational score from the halfway line.
Saints now must wait to find out who they are to face in the Premiership Rugby Cup semi-finals, with the final pool matches of this season's competition played next weekend.