Coventry City began the new League One campaign in fine style with a comfortable opening day victory over Wigan Athletic at the Ricoh Arena.
Armstrong was the Sky Blues hero as hit the first two professional goals of his career in a memorable City debut.
He opened the scoring after latching onto Jim O'Brien's through ball to sprint through and slot home.
With the Latics attacking for a second-half equaliser, City caught them on the break and Armstrong was on hand to meet John Fleck's cross with a deft touch from five-yards to bring the majority of the 13,131 crowd to their feet.
He then nearly capped his performance with a hat-trick goal but was denied by the post with 15 minutes to play.