After a goalless first half, Dons defender George Francomb’s looping header into his own net from Sean Clare’s free-kick put the hosts in front in the 62nd minute.
Lyle Taylor pulled his side level from the penalty spot five minutes later after Luke O’Neill bundled former Gills striker Cody McDonald over in the box. The goal was the Dons striker’s sixth in as many games.
However the two sides were level for less than 120 seconds, as Clare’s corner was bundled in at the near post by Gillingham defender Max Ehmer for his first league goal since February.
But Forrester earned the Dons a draw six minutes from time, volleying in following a well-worked corner involving Taylor and Deji Oshilaja.
In a largely scrappy match, Tomas Holy was the busier of the two goalkeepers, most notably denying McDonald with a superb leg save to keep out the Wimbledon striker’s low shot on the half-hour.
England manager Gareth Southgate has claimed that the country needs to boot racism out of its own football before criticising World Cup hosts Russia.
Newcastle have been linked with a shock move for former Sunderland goalkeeper Simon Mignolet during the summer.