Northampton recovered from being 0-21 down but lost 30-27 as a last ditch Freddie Burns penalty saw Leicester win at Welford Road on Saturday.
Despite leading 21-0 at one stage, the Tigers were relieved to get the victory, while Northampton could feel hard done by to only come away with a losing bonus point.
The torrential downpour added to the excitement with ex-Leicester player Jamie Gibson bringing his current employers back into the contest.
A record crowd at Welford Park were treated to one of the best matches of the Premiership season, which saw Leicester open up a seven-point gap in the table over their local rivals.
With less than two minutes on the clock, Leicester took the lead as Matt Smith touched down on the right after selling the visitor's defence with a dummy.
Owen Williams converted for the sweetest start. Following the bright opening, the game took a turn for the worse with neither side able to dominate, but after the first scuffle of the game, Leicester extended their advantage, with Lachlan McCaffrey getting over the line. Williams unconvincingly added the extras.
There was no period of rest following the second try however, as Tigers' kicker Williams got five points of his own, having been played through by Ben Youngs. Williams converted once more.
On the half hour mark, Saints were awarded a penalty on the Tigers 22. JJ Hanrahan kicked the first three points of the afternoon for the away side.
With the first half coming towards a conclusion, Williams was forced off for the hosts with an injury, before Saints scored their first try of the game through Teimana Harrison, who drove forward after catching at the corner. Hanrahan converted to make the score 21-10 at the break.
Northampton picked up where they left off, reducing the deficit through George North, who broke through having intercepted after a long spell of possession from the hosts. Hanrahan made no mistake with the conversion, putting just four points between the sides.
The travelling fans were up in arms as the try which would have given them the lead was ruled out for a high tackle. Tighthead prop Paul Hill had done superbly to run in from distance, but to no avail.
Shortly after, Manu Tuilagi came on for the hosts, making his first appearance in 14 months. His presence helped the hosts, who earned two penalties in quick succession, Burns successful with both.
Dan Cole was sent to the sin bin in the aftermath of the second penalty, and Saints took advantage, with former Leicester flanker Gibson sliding over the line after breaking through a maul, with Stephen Myler kicking the extra two points.
And despite having Cole back on the pitch, the hosts were brought back to level terms for the first time since the second minute, thanks to Myler's penalty, making it 27-27.
But after a grandstand effort, much of the visitor's hard work was undone when Burns scored a penalty on the Saints 22 with the final touch of the game.
Tries: Smith, McCaffrey, Williams
Cons: Williams 3
Pens: Burns 3
Yellow Card: Cole
Tries: Harrison, North, Gibson
Cons: Hanrahan 2, Myler
Pens: Hanrahan, Myler
Leicester: 15 Telusa Veainu, 14 Peter Betham, 13 Mathew Tait, 12 Matt Smith, 11 Adam Thompstone, 10 Owen Williams, 9 Ben Youngs, 8 Lachlan McCaffrey, 7 Brendon O'Connor, 6 Mike Fitzgerald, 5 Graham Kitchener, 4 Sebastian de Chaves, 3 Dan Cole, 2 Tom Youngs (c), 1 Marcos Ayerza.
Replacements: 16 Harry Thacker, 17 Logovi'i Mulipola, 18 Fraser Balmain, 19 Laurence Pearce, 20 Tom Croft, 21 Sam Harrison, 22 Freddie Burns, 23 Manu Tuilagi.
Northampton: 15 Ben Foden, 14 Jamie Elliott, 13 George North, 12 Luther Burrell, 11 Tom Collins, 10 JJ Hanrahan, 9 Lee Dickson (c), 8 Sam Dickinson, 7 Teimana Harrison, 6 Jamie Gibson, 5 Victor Matfield, 4 Courtney Lawes, 3 Paul Hill, 2 Mikey Haywood, 1 Alex Waller.
Replacements: 16 Matti Williams, 17 Ethan Waller, 18 Gareth Denman, 19 Christian Day, 20 Tom Wood, 21 Tom Kessell, 22 Stephen Myler, 23 Harry Mallinder.
Referee: Wayne Barnes
Assistant Referees: Tim Wigglesworth, Peter Allan
TMO: Sean Davey