Winger Paul Diggin raced in for two tries and in-form Ben Foden scored the third as Northampton extended their unbeaten home run to 28 matches with victory in a sell-out Guinness Premiership derby.
An uncharacteristic off-day by goalkicker Stephen Myler, who had a terrible first half with the boot, made the task more difficult for Saints than it should have been. But they were good value for their win as they repelled a fightback by Tigers whose points all came from England fly-half Toby Flood, who added a second-half try and conversion to his two first-half penalties.
Leicester had forwards coach Richard Cockerill in charge for his second match since director of rugby Heyneke Meyer returned home to South Africa on compassionate leave because of family illness. The visitors threatened to repeat the fightback which saw them overturn a 19-point deficit to beat Bath last weekend but Northampton maintained their discipline.
The hosts had dominated a fast and furious opening spell and went into a 10-0 lead, with Diggin striking twice. The first try came in the 12th minute when Northampton won a lineout on the left. They moved the ball through several pairs of hands before full-back Foden burst into the line to provide the final pass which sent Diggin diving over near the right touchline.
Ten minutes later and with Saints putting Leicester's defence under enormous pressure, the winger then grabbed his third Premiership try of 2009, popping up in the middle of the attacking line to take a short pass from Myler and breach the defensive line. Only poor kicking from the usually accurate Myler, who is keeping All Blacks legend Carlos Spencer out of the Saints starting line-up, prevented the home side from establishing a dominant lead.
The former rugby league player drew a blank in the first half, squandering a possible 16 points as he failed with three penalties and both conversion attempts as well as falling short with a drop kick which was well within his normal range. The misses enabled Leicester, who had taken a pounding for much of the opening 40 minutes, to remain in touch.
Flood, who had missed an early 40-metre penalty, made kicks from close range in the 26th and 35th minutes after Northampton were penalised for ruck offences in front of their own posts. But Northampton were in no mood to give up the chance of a first Premiership victory over the Tigers for four-and-a-half years.
They continued to attack with flair and ambition and Foden, the full-back who prefers to play at scrum-half, produced a brilliant stop-go dummy to split Leicester wide open as he burst through to touch down behind the posts and present Myler with the simplest of confidence-restoring conversions to put the home side 17-6 ahead.
Leicester called up their big guns from the bench in the 55th minute, sending on former England captain Martin Corry for lock Marco Wentzel and Italian prop Martin Castrogiovanni for Boris Stankovich. Their arrival seemed to revive the Tigers who got right back in the game and cut the deficit to four points after scrum-half Julien Dupuy took a quick tap penalty to send Flood in for their first try.
But Northampton dug deep to survive a rocky spell and were back on the the attack when they were awarded a last-second penalty which Myler booted into touch with the final kick of the match before his side took a standing ovation from their supporters.
Northampton boss Jim Mallinder was full of praise for two-try local hero Diggin following the game. "He's only small but he's got a big heart. We've got a bit of competition there and he's keeping some key personnel out of the team," Mallinder said. "He's a local Northampton lad who went to the boys' school down the road and what he's doing is fantastic."
Mallinder also backed Foden for a place in Martin Johnson's England squad after an eye-catching display. "He backed up last week's performance. It was a fantastic performance and then he has the ability to switch to scrum-half when Lee Dickson got a little bit of cramp near the end.
"He picks lines really well, he's got pace and he's got strength as well. He's got the ability to fend off that first tackler and stay on his feet and has a good kicking game as well. I don't know what he [Johnson] is looking at but I think he's got to come into his consideration."
Leicester's stand-in coach Richard Cockerill, in charge for a second match after director of rugby Heyneke Meyer returned home to South Africa on compassionate leave because of family illness, had no complaints. "We didn't control the ball, we turned it over too much and we had to ride the storm in the first 25 minutes but we just couldn't build enough pressure.
"Saints took the game to us, they ran very hard and three tries to one, you can't hide from that fact. If they had kicked their penalties and conversions they might have been out of sight by half-time. You have to take your hat off to the way they played."
Northampton: Foden; Diggin, Clarke, Downey, Lamont; Myler, Dickens; Smith, Hartley, Murray, Fernandez Lobbe, Kruger, Easter, S Gray, Hopley.
Replacements: Mayor for Downey (77), Reihana for Dickens (71), Tonga'uiha for Smith (53). Not Used: Shields, Day, Lawes, Spencer.
Leicester: G Murphy; J Murphy, Rabeni, Mauger, Smith; Flood, Dupuy; Stankovich, Chuter, White, Wentzel, Kay, Croft, Herring, B Deacon.
Replacements: Hamilton for J Murphy (41), B Youngs for Dupuy (61), Castrogiovanni for Stankovich (56), Corry for Wentzel (56), Newby for Herring (11). Not Used: Kayser, Vesty.
Att: 13,582
Ref: Wayne Barnes (England).