The 47-year-old insisted his comments had nothing to do with club rivalries.
"He plays for England and I hope he does well," Merson added. "Don’t think I sat there the other night and was upset for him when he scored. I was well pleased.
"But he’s just got back at Tottenham for the last seven or eight games. Where has he been all season?
"And you can’t say I am anti-Tottenham. There is no bigger fan of Harry Kane than me. I think he is unbelievable. You can’t throw that Arsenal-Tottenham thing at me."
Townsend had been keenly awaiting a response from Merson.
"I am eagerly awaiting it," he said with a smile that did not disappear for one second during his round of post-match interviews.
"As soon as the squad was announced two weeks ago, it has been going over in my head. He said it when the squad was announced – that I should be nowhere near the squad.
"As soon as the goal went in, I was just desperate to get that tweet out!
"It didn’t really annoy me. It had kind of just given me the extra incentive to silence a few critics and hopefully I have done that as I always have done."
Townsend has had enough highs and lows in his career to know the sweet right-foot drive into the bottom corner of Gianluigi Buffon’s goal does not mean the critics will be silenced forever.
Less than a year after scoring an equally breath-taking goal on his international debut against Montenegro in October 2013, Townsend could not hold down a first-team place at Tottenham, let alone England.
Townsend started just two Barclays Premier League games before the turn of the year, but he is now a regular under Mauricio Pochettino.
A level-headed and grounded man, he knows competition is so tough at club and international level he must continue improving.
"I have still got things to prove to people," he said.
"You can never stop proving things to people, but I think every time I have put on an England shirt I have done myself justice, I have done Roy Hodgson justice and the nation justice.
"I was a bit disappointed with (Merson’s) comments but again I have come on the pitch and silenced them.
"I don’t think I am at my best form but this is the best form I have produced this season.
"I am slowly building my confidence back to where it was and hopefully from now until the end of the season, I can get more games in the Spurs team and for England in the summer and get back to the football I was producing last season."