Northampton Saints' 52-30 Premiership win over Wasps was soured as Wales winger George North suffered a serious head injury.
North, who sustained two severe blows to the head in Wales' opening Six Nations defeat to England on February 6, was knocked unconscious in the act of scoring his second try at Franklin's Gardens on Friday.
Wasps' Nathan Hughes caught North in the head with his knee and was sent off. North received lengthy treatment before being taken off on a stretcher, although he was reported to be awake in the dressing room as the second half started.
The visitors were leading 20-8 prior to the incident, but Northampton capitalised on the man advantage to come from behind.
Northampton ran in seven tries on their way to victory, with Ahsee Tuala scoring a brace as Christian Wade's hat-trick for Wasps was rendered immaterial.
The triumph leaves Northampton 14 points clear at the top of the Premiership.