It was a costly foul conceded by Magpies defender Lee Canoville on Matt Done which led to defender Wes Baynes' free-kick finding Roberts at the far post and he beat a defender and keeper Russell Hoult for what could be a golden goal.
It had been a scrappy and not surprisingly poor quality game until the goal which then led to the visitors having to attack, but they could have made sure of all three points in the first half.
In the space of a few minutes, Danny Crow found himself in a one-on-one with Gavin Ward but he hit the chance straight at the keeper and the ball was scrambled away.
Crow missed another chance and then Ryan Jarvis also hit wide and Wrexham lived to fight on.
Little was seen of the Wrexham attack and in fact it was a Baynes and a Levi Mackin effort which were the only shots to have troubled Hoult.
After Roberts' goal both keepers made tremendous saves. First Ward somehow kept out an effort from Jason Lee and then immediately at the other end, Hoult made a brilliant one-handed save to keep out a shot from Marc Williams.
In injury time and with County desperate for an equaliser, the last chance fell to Richard Butcher but he hit the ball over the home bar.