Saints boss Jim Mallinder expressed his anger at referee Wayne Barnes after Saints suffered a 22-16 defeat to local rivals Leicester Tigers at Franklin’s Gardens.
The director of rugby followed Barnes down the tunnel after he called time on the game with Northampton lining up a lineout five metres out.
The official deemed the clock was dead and that left Saints without a chance to attempt to win the game, with Barnes being roundly booed as Phil Dowson tried to stop Mallinder getting to the man in yellow.
Leicester won the game thanks to 17 points from Owen Williams and a try from Anthony Allen as Saints were made to pay for missed kicks.
Young fly-half WIll Hooley failed with three attempts and James Wilson with one as both players ended the day with three points to their name.
Ethan Waller’s try two minutes from time added to Kahn Fotuali’i’s first-half score to give Saints hope, but Barnes’ whistle ended Saints’ hopes of a comeback.
Leicester are now seven points adrift of Mallinder’s men in third with four games of the season remaining.
And they claimed the win despite late disruption, with Scott Hamilton coming in for Mat Tait at full-back before kick-off and Sam Harrison replacing David Mele on the bench.
Saints had no such issues and they started well, snuffing out a Tigers attack before winning a penalty at the other end.
It was an early test for youngster Hooley, who nudged the ball through the posts to give his side a welcome lead.
Tigers responded by trying to make ground with batterings rams Tuilagi and Vereniki Goneva, with a kick through just proving too long for the Fijian wing.
Goneva soon threatened again, but was stopped in his tracks by George North and Ben Foden, who stood strong to push the Tigers juggernaut into touch.
It didn’t take long for tempers to fray and after a TMO review for an alleged bite on Tom Youngs, the away side made their pressure pay through Allen’s score in the corner.
There had looked to be a block on North in the build-up, but no action was taken and Williams made it 7-3 with the conversion.
Saints couldn’t get out of their own half and after Luther Burrell got isolated, Tigers got over him to win a penalty, which Williams slotted to extend his team’s lead.
The Tigers were making all the metres and, crucially, were making no errors as they continued to boss proceedings.
Barnes drew more boos from the home fans as he awarded another penalty the way of the visitors, with Williams making it a 10-point lead 11 minutes before the break.
Saints had the chance for an instant riposte, but Hooley pushed a simple penalty attempt wide of the posts.
And things were to get worse for the home side as Dylan Hartley was forced off with a shoulder injury and Salesi Ma’afu with a leg problem.
Saints needed something to go their way. They needed a response, and were so close as Jamie Elliott’s kick ahead gave them a chance to press Tigers on the line.
Dowson was denied out wide by Goneva before Saints had their try, Fotuali’i sniped to find a gap to dive over the line.
Hooley again missed a kick he would have expected to make, though, to leave Tigers five points up at the break.
The try late in the half fuelled Saints’ belief and they played with more purpose in the opening stages of the second period.
But their profligacy from the tee was costing them dear, with Hooley again off target with an effort from distance.
Saints quickly sent for Wilson, with Hooley, who had been impressive in open play, taken off.
It looked set to come down to the kicks that weren’t made and those that were, with Williams maintaining his 100 per cent record with another penalty.
Wilson soon responded, though, thumping the ball through the posts emphatically to wipe away some of the frustration of earlier kicks.
But Saints’ hard work was again undone, as Williams once more made his mark with a penalty.
And the Welshman soon swept the game further out of Saints’ reach with another well-struck penalty to prompt roars from the Tigers faithful.
The away side looked set to record a comfortable win, but yellow peril put them in trouble towards the end.
Ben Youngs was sin-binned for killing the ball five minutes before full-time and Goneva was followed him off the pitch a minute later.
Saints punished the 13 men as Waller found his way over in the corner, but Wilson’s missed kick left the gap at six points with two minutes to go.
Leicester held out, but not without a controversial conclusion, with Barnes in the spotlight once again.
The Tigers fans celebrated and Saints were left to reflect on another derby-day disappointment.
Saints: Foden; Elliott (L Dickson 65), G Pisi, Burrell, North; Hooley (Wilson 60), Fotuali’i (L Dickson 65), A Waller (E Waller 62), Hartley (Haywood 33), Ma’afu (Mercey 37); Lawes, C Day; Clark (van Velze 66), Dowson, Wood.
Replacements not used: Craig, K Pisi.
Leicester: Hamilton; Goneva, Tuilagi, Allen, Thompstone (Harrison 76); Williams (Flood 73), B Youngs; Ayerza, T Youngs, Mulipola (Balmain 76); Deacon (Kitchener 65), Slater (c); Gibson, Salvi, Crane.
Replacements not used: Hawkins, Stankovich, Matera, Smith.
Referee: Wayne Barnes