Tigers withstood a Saints fightback after being reduced to 13 men in the final 10 minutes of Saturday's clash at Franklin's Gardens following yellow cards for Ben Youngs and Vereniki Goneva.
Saints trailed 22-11 when Goneva became the second Tigers player to be sent to the bin and the hosts crossed immediately after through Ethan Waller.
But resolute defending in the closing moments prevented a further Saints score and ensured Tigers inflicted a first home league defeat of the season on the Saints,
Tigers have now gone 10 games undefeated in all competitions against their East Midlands neighbours and it was a sixth win in a row for Richard Cockerill's men as they leapfrogged Bath into third in the table.
Tigers had controlled large parts of the game, scoring the first try through Anthony Allen following Ben Youngs’s stunning 20m pass.
And despite a try for Kahn Fotuali’i, it was with the boot of Owen Williams that effectively proved the difference on the scoreboard, the fly-half kicking 17 points in a flawless display off the tee.
Tigers retained the same starting XV that beat Exeter Chiefs last week after the late withdrawal of Mathew Tait. Tait had been named at full-back but was replaced by Scott Hamilton. Matt Smith took Hamilton’s place on the bench.
Tigers included Pablo Matera on the bench in place of Thomas Waldrom, and David Mele was a late withdrawal among the replacements, his place going to Sam Harrison.
Tigers had some early pressure in the Saints half, keeping the ball in hand and going through the phases, but met solid defence. Ben Youngs eventually tried to mix the attack with a chip ahead, Adam Thompstone tapped it back but Owen Williams was unable to gather.
At the other end, Williams’s clearance found Wales wing George North on the left flank. He was well tackled by Williams but when he failed to roll, Will Hooley landed the penalty to give Saints a fifth-minute lead.
Tigers were again patient, going through the phases with Jordan Crane, Ed Slater and Logovi’i Mulipola leading the charge. Julian Salvi then slipped a grubber behind the defence which evaded Vereniki Goneva and George Pisi and ran dead in-goal.
Tigers had lots of possession and territory and a smart passing move allowed Goneva to test Ben Foden’s defence, the Saints full-back doing well to force him into touch.
Slater then barrelled his way past Courtney Lawes to within 5m of the line. Ben Youngs secured quick ball but his pass was knocked on, giving Tigers the put-in at the scrum from which they eventually made their early supremacy pay.
Goneva and Crane consolidated the position off the back of the scrum before Slater was stopped just short. Tigers had the advantage of a penalty and Ben Youngs picked out Allen on the right flank with a stunning 20m pass for the centre to score unopposed. Williams landed the touchline conversion to put Tigers 7-3 ahead after 18 minutes.
England lock Courtney Lawes was caught in two minds as he received a pass from Hooley in his own half. He was well tackled by Crane and then failed to release the ball giving Tigers the penalty on the Saints 10m line, which Williams landed to extend the lead to 10-3.
Tigers continued to have much of the possession and were running the ball as much as possible. A break by Hamilton was continued by Allen to take Tigers into Northampton territory again. Goneva went on his own at a ruck and was well tackled but the Saints defender failed to release giving Williams another shot at goal. The fly-half made no mistake with his penalty to move Tigers 13-3 ahead 10 minutes before the break.
Foden’s break gave Saints some momentum for the first time in the game. He had Fotuali’i in support with room to run into but he crabbed across field to close the space. Saints retained possession and a couple of phases later Salvi was pinged for going off his feet. Dylan Hartley took a bang in the attack and was replaced by Mike Haywood.
In the meantime, Hooley took the penalty but pushed it across the posts. Foden then launched an up-and-under straight out of play as Saints made a series of unforced errors.
Tom Mercey then replaced Salesi Ma’afu in the Saints front row as the hosts came more into the game.
Jamie Elliott’s gubber had Ben Youngs in difficulty running back towards his own line. Tom Wood swooped on the loose ball and was stooped just short. Saints swung the ball to the left where Phil Dowson was in plenty of space but he was tackled by Goneva.
Referee Wayne Barnes came back for an earlier advantage. Saints opted for the lineout and while Tigers defended the initial drive, Fotuali’i darted down the side of the ruck and over for the try. Hooley missed a simple conversion as Tigers led 13-8 at the break.
Tigers started the second period strongly, controlling the possession to force their way into the Saints half. Ben Youngs’s snipe was stopped on the Saints 22 before his brother Tom was whistled at the next phase for holding on.
Mulipola then broke through a couple of tackles in midfield with a trademark run but a handling error at the next phase meant Tigers were unable to make the most of the position.
Instead, Saints were given the first opportunity of the second period to put points on the board after Tuilagi was whistled for a high tackle on Alex Waller. However, Hooley was wide with his kick from a central position as Tigers stayed 13-8 ahead.
Goneva eyed a break away when he collected a bouncing ball on halfway but he was well stopped by Pisi. James Wilson then replaced Hooley for the Saints.
But it was the Tigers fly-half who had the next kick at goal after the Leicester pack won a scrum penalty, and Williams maintained his 100 per cent record to move Tigers into an eight-point lead going into the final 20 minutes.
Saints had Tigers under pressure when North returned Goneva’s kick from deep. However, Elliott knocked on North's pass just as a gap appeared to open in the Leicester defence.
Tigers were unable to clear from the scrum, however, and the Saints drew a penalty, which Wilson landed to cut Leicester’s lead to 16-11.
Tigers introduced Graham Kitchener for Louis Deacon and Ethan Waller replaced Alex Waller for Saints.
The hosts couldn't escape their 22 from the restart and were pinged for holding on. Williams knocked over the penalty to restore Leicester’s eight-point advantage.
Lee Dickson replaced Elliott, forcing a reshuffle in the Saints backs. Fotuali’i went to fly-half with Wilson moving to the wing.
Saints were then ruled offside at a lineout and Williams landed the penalty from an almost identical position to his previous kick. It moved Leicester 22-11 ahead with 14 minutes remaining.
Wilson was then alert to snuff out the danger as Thompstone swooped on a loose pass on halfway.
Then it was Tigers’ turn to breath a sigh of relief when Luther Burrell knocked-on Fotuali’i's pass just inside the Leicester half with the Tigers defence struggling to get across.
Williams and Tom Youngs were replaced by Toby Flood and Rob Hawkins respectively with 11 minutes left.
A huge period in the game followed as Saints went for the corner with successive penaltes. But Tigers defended the drive brilliantly, preventing the ball coming back and earning the scrum put-in. Crane then cleaned up a scrappy set-piece and Youngs found touch on the 22.
North, Northampton's Lions wing, made a thrilling break from deep and was stopped by a combination of Hamilton and Youngs. However, Youngs was shown a yellow card for failing to release after the tackle as Saints players flooded forward in support.
Saints sensed a way back into the game and almost took it when Ken Pisi received Fotuali’i’s long pass on the right touchline but was bundled into touch by Hamilton and Thompstone at the corner flag. It was Thompstone’s last contribution and he was replaced by Harrison.
Goneva was then shown a yellow card for a high tackle leaging Tigers down to 13 men for the last six minutes.
Saints made the numerical advantage count immediately when Wood sent Waller over at the corner for the try. Referee Barnes went to his television match official to check for a forward pass before awarding the score.
Wilson took on the touchline conversion but it drifted wide leaving Tigers 22-16 ahead with two minutes on the clock.
Tigers tried to run down the clock by keeping it tight on halfway, but they were pinged for going off their feet with 30 seconds left.
Tigers had five men in the back-line for the lineout, but the Saints were unable to work the scoring opportunity as Manu mopped up a loose ball in the left corner and found touch for the final act of the game.