The victory, which extended their winning run to five matches, saw Martin Paterson’s team climb to second in the League Two table and to within five points of leaders Bromley.

Gareth Ainsworth’s side had made an encouraging start to the game before Robertson’s finish saw them fall behind in the 27th minute.

Tyrese Hall and Maz Kouhyar, County’s Afghanistan international, had already had chances – both created by Nick Tsaroulla – when Robertson threaded the ball home at Glenn Morris’ near post after combining with Ollie Norburn and taking advantage of Seb Palmer-Houlden’s indecision.

Tsaroulla went close to doubling County’s advantage with a curling attempt before Kouhyar followed suit.

Although Palmer-Houlden had earlier threatened for Gillingham, the interval did not curb the hosts’ momentum with Robertson nearly converting a long-range free-kick soon after the restart.

But County were indebted to James Belshaw for making some fine saves, including one to deny substitute Sam Vokes, as Gillingham applied heavy pressure during the closing stages.