The prolific striker celebrated his first start since dislocating an elbow seven weeks ago with a double.
The former Grays man opened and completed the scoring as Darren Ferguson's side made light work of a sorry Huddersfield, who have now conceded nine goals in two games.
Mclean broke the deadlock with a rasping 12th-minute finish after George Boyd had danced into the box and then provider turned goalscorer 12 minutes later when Boyd doubled the lead after being released from midfield by Paul Coutts.
There was further misery for Huddersfield after the break when Chris Whelpdale headed a classy third goal after being picked out by a pinpoint Boyd cross, before Mclean's routine shot slipped under Matt Glennon's body.
There was more misery for Town in stoppage-time with skipper Chris Lucketti dismissed for a professional foul on home striker Craig Mackail-Smith.