Northampton took advantage of Solomone Kata's red card to beat local rivals Leicester 40-17 on Saturday and remain out in front at the top of the English Premiership.
Leicester went in ahead at halftime leading 10-6 after a scrappy 40 minutes that included a yellow card apiece.
But the Saints showed their class after the break, pulling away with a helping hand from Kata, who was dismissed for a dangerous high tackle on Fraser Dingwall with the score at 18-17 in Northampton's favour.
The home side scored five tries in total during the second period to all but secure a play-off spot.
The loss means Leicester's hopes of a top-four finish hang by a thread.
They are three points off the top four having played a game more than their rivals.
Bath moved up to second after battling to a 26-14 win at Exeter.
The visitors avenged their 21-15 Champions Cup defeat to Exeter a fortnight ago to leave the Chiefs in real danger of missing out on the top four.
Alfie Barbeary, Max Ojomoh, Miles Reid and Ben Spencer scored Bath's tries with Spencer adding three conversions.
Tom Parton scored the fastest hat-trick in Premiership history as Saracens ran in seven tries to thrash Gloucester 46-24.
Parton touched down three times a 13-minute spell inside the first 20 minutes as Saracens remain in third.
Josh Hathaway also scored a hat-trick for Gloucester but their hopes of qualifying for next season's Champions Cup are fading as they are 10 points adrift of the top eight.