Coming on as substitute in the 2–1 win over Stevenage on 12 January 2013, Coppinger reached the milestone of 300 league appearances for Doncaster, one of only ten players to do so at the club. On 27 April 2013, in an incredible final match of the season at Griffin Park, Coppinger scored the winning goal in a 1–0 away victory over Brentford in the final seconds of five minutes of added time just moments after Brentford's Marcello Trotta had hit a penalty against the crossbar. If Brentford had won, they would have been promoted and Doncaster would have had to compete in the play-offs. As it was, his goal put Doncaster one point above Bournemouth and they were crowned champions.