If there was a manager’s player-of-the-match then there was a leading contender for Gillingham boss Mark Bonner on Saturday. Robbie McKenzie’s early goal put the Gills in front after a tricky start and the midfielder ended the game in defence after captain Max Ehmer was sent off – playing a key rearguard role as Chesterfield looked to capitalise on their man advantage. More: Manager reveals why they had to bring in a new goalkeeper The Gills held on for a 1-0 win as they remain top of League 2 after four games. “Robbie McKenzie’s performance was unreal,” said the manager. “Centre midfield, goa…