Cobblers forward Harry Smith held his hands up and accepted he was to blame for Port Vale's opening goal during Saturday's 1-1 draw.
Manager Keith Curle's decision to opt for zonal marking came in for some criticism after his side conceded from a set-piece for the second game running.
David Amoo was left unmarked to head past Steve Arnold on 26 minutes at Vale Park, but Curle insisted afterwards that individual errors, rather than the system, were to blame.
And striker Smith took to social media later the same evening to take responsibility, saying: "Hands up completely for their goal today, really really sh*t defending if I’m honest. wasn’t particularly my day, disappointed!. but lads dug deep for a hard fought point at a difficult place- on we go!"
Ryan Watson scored in first-half stoppage-time to grab a point for the Cobblers, their first of the new season.
Winger Nicky Adams tweeted: "Never an easy place to go. Great response from the boys. Top support as usual."
It was a landmark day for Sam Hoskins and he added: "Not the best performance but a good point away from home today. Also very pleased to have played my 150th game for the club onto Tuesday night."