The 24-year-old, who joined the Magpies from Tottenham Hotspur for £12m in the winter transfer window, made his home debut during the 1-0 win over West Bromwich Albion.
He was replaced by Ayoze Perez in the 88th minute, when he was given a standing ovation by those inside St James' Park.
"Humbled by the reception I received today on my home debut but more importantly massive 3 points and thoroughly deserved," Townsend wrote on Twitter.
The victory lifted Newcastle out of the relegation zone at the expense of Norwich City.