|Northampton Saints (27) 52|
|Tries: North 2, penalty, Corbisiero, K. Pisi, Tuala 2 Pens: Myler 3 Cons: Myler 4|
|Wasps (20) 30|
|Tries: Wade 3 Pens: Lozowski 3 Cons: Lozowski 3|
Premiership leaders Northampton beat 14-man Wasps 52-30 but their victory was soured by a worrying head injury suffered by Wales wing George North.
North was knocked unconscious in the act of scoring his second try.
Nathan Hughes caught North late with a knee to the head and was sent off, while the 22-year-old received several minutes of treatment before being carried off on a stretcher.
Christian Wade's hat-trick of tries proved to be vain for Wasps.
Northampton are 14 points clear at the top of the table but their main concern will be over North, who was reported to be awake in the dressing room as the second half commenced.
Afterwards, director of rugby Jim Mallinder said North may be available to play in their Champions Cup match at Clermont next weekend, telling BT Sport: "He clearly took a bang straight to the head but he came round and he sat up in the changing room and managed to have a little sing-song.
"We'll look after him and hopefully he'll be okay next weekend."
However, after sustaining two head blows in Wales' Six Nations defeat by England in February and missing the subsequent match against Scotland, there are sure to be more questions about the player's welfare and the current protocols regarding those who suffer concussions.
Prior to the incident that led to North's premature exit, Wasps had been in control and looked certain to take a lead into half-time, but forward Hughes's dismissal turned the match in Northampton's favour.
Wade's counter-attacking opener from distance and a second superbly created by fly-half Alex Lozowski sandwiched North's first, which came courtesy of Stephen Myler's excellent cross-field kick.
The sides swapped penalties to leave Wasps 12 points clear at 20-8, but Hughes's red card changed the game.
A powerful rolling maul earned the hosts a penalty try and prop Alex Corbisiero barged his way over to secure a bonus point for Saints before the interval.
Mallinder's men struggled to make the advantage of an extra man count, with Wade's hat-trick try out wide bringing Wasps to within three points, before a Ken Pisi score and two more from replacement Ahsee Tuala in the final 10 minutes made the game safe for the Saints.
Myler's tally of 17 points took the fly-half ahead of Paul Grayson as Northampton's all-time leading scorer of points in the Premiership.
Wasps director of rugby Dai Young:
"First of all I hope George is okay, Nathan has gone looking for him to make sure he is okay - he is not that type of person.
"When you slow anything down it looks worse than it actually is and when the crowd get on the referee's back - a young referee - there is only going to be one decision.
"We felt it was a bit harsh.
"That eight minutes before half-time killed us, and the last eight minutes made the scoreline look a lot worse. It was a little bit cruel we didn't come away with a bonus point."
Northampton Saints: Wilson; K. Pisi, G. Pisi, Stephenson, North; Myler, L. Dickson; Corbisiero, Hartley, Ma'afu, Lawes, C. Day, Wood, Clark, Manoa.
Replacements: Haywood, A. Waller, Denman, S. Dickinson, Fisher, Fotuali'i, Waldouck, Tuala.
Wasps: Miller; Wade, Daly, Downey, Tagicakibau; Lozowski, Simpson; Mullan, Shervington, Cittadini, Cannon, Myall, Johnson, Young, N. Hughes.
Replacements: McIntyre, Swainston, Gaskell, E. Jackson, Thompson, Weepu, G. Hughes, W. Helu.
Referee: Craig Maxwell-Keys