Leicester Tigers extended their unbeaten run to seven matches in all competitions as they beat Northampton in a thrilling Premiership game.
After red cards for Alesana Tuilagi and Tom Wood saw both sides reduced to 14 men, tries from Matt Smith and Steve Mafi put the Tigers 15-6 ahead.
Chris Ashton and Tom May went over for Saints either side of Ben Youngs's try.
Phil Dowson then put Saints in front but Horacio Agulla secured a thrilling bonus-point win for Tigers.
Fly-half Ryan Lamb kicked the visitors into a 3-0 lead before Leicester counterpart Toby Flood levelled soon after.
The sides were reduced to 14 men each after England winger Ashton's tackle on Alesana Tuilagi, dragging him out of play by his hair, resulted in a fracas which saw the Samoa international winger and Saints flanker Wood sent from the field.
With the game now sparked into life outside centre Smith held off a strong challenge from Ben Foden to touch down right in the corner for the opening try of the match.
Leicester's second came soon after when flanker Mafi burst through four weak tackles to cross the line, with Flood adding the extras.
Lamb and Flood then added a penalty each as the Tigers went into the break 15-6 ahead.
England fly-half Flood added three more points with his boot before Ashton latched on to a Foden pass to score in the corner.
Youngs then drove over for Leicester's third try, after a television review, as the hosts looked to be back in control.
But that try seemed to spur the visitors into action as May went over in similar fashion, with Stephen Myler adding the extras, before Dowson touched down behind the posts to level the scores.
Myler's second conversion took Saints into the lead for the second time in the match.
But just when it looked like the momentum was with Northampton the game suddenly swung back the other way as Leicester counter-attacked from deep and second row Ed Slater dummied and fed Argentina winger Agulla, who ran 50 metres before mimicking an Ashton swallow dive to touch down.
Flood added the conversion as Leicester climbed to seventh and Saints were left to make do with a losing bonus point.
Leicester coach Richard Cockerill told ESPN:
"You have to be a little bit careful, Ashton dropped a shoulder into Geordan Murphy after a kick and the tackle on Alesana, he's dragged him by his hair into touch.
"I don't think there was a lot going on involving Alesana at all and he got the red card, we'll have to take a look and review it.
"He could miss Europe next week, which is massive for us on a massive call from the referee - Alesana hasn't thrown a punch, so what's he been sent off for?
"It's disappointing because I think the game was spoilt from that point. I've not seen all the angles but a yellow card for whoever they wanted to blame is enough there."
Northampton director of rugby Jim Mallinder told BBC Radio Northampton:
"[For the red cards], what I could see there was a lot of bodies going in. You don't expect punches to be thrown and I don't think it was that bad. You've got 25,000 people there and you're looking for an edge; it's part of local rivalry.
"Maybe just to settle the game down a couple of yellow cards might have helped the game. The nature of the sending-offs meant they had extra in the forwards and we had it in the backs and in that period they took control a bit.
"We showed spirit and a bit of composure to come back into the game and with two minutes to go we were ahead and we should have looked after the ball."
Leicester: Murphy (capt); Agulla, Smith, Twelvetrees, A. Tuilagi; Flood, B. Youngs; Ayerza, Chuter, Cole; Deacon, Skivington; Mafi, Salvi, Waldrom.
Replacements: Hamilton for Murphy (77), Harrison for B. Youngs (77), Stankovich for Ayerza (77), Castrogiovanni for Cole (58), Woods for Waldrom (77). Slater for Skivington (75).
Not Used: Hawkins, Staunton.
Sent Off: A. Tuilagi (13).
Northampton: Foden; Ashton, Pisi, May, Elliott; Lamb, Dickson; Tonga'uiha, Hartley (capt), Mujati; Lawes, Sorenson; Dowson, Wood, Wilson.
Replacements: Clarke for May (73), Myler for Lamb (61), Haywood for Hartley (76), Manoa for Sorenson (41), Nutley for Wilson (56).Not Used: A. Waller, Doran-Jones, Roberts.
Sent Off: Wood (13).
Referee: Wayne Barnes (RFU).