Neal Ardley's side began brightly before taking the lead in the 19th minute when Rob Milsom's cross was touched into the path of Mackail-Smith by Virgil Gomis, and the on-loan Wycombe man volleyed home from 20 yards.
Notts continued to push forward as Jon Stead went close with a header which went just wide, while Enzio Boldeiwjn had a pop but it was straight at Mansfield goalkeeper Jordan Smith.
Although David Flitcroft's side stepped up a gear in the second half, with Nicky Ajose and CJ Hamilton both trying their luck to no avail, the visitors never really threatened Magpies loanee stopper Ryan Schofield, with not one shot on target registered.
Indeed, Notts had a great chance to kill the game off late on when Kane Hemmings just failed to connect with a Mitch Rose cross, but unlike last season, this time Notts held film and claimed all three points to initially move to one point of safety - now two - with one game in hand on the two sides above them.
Pride of Nottingham vlogger ARLukomski was at the San Sirrel to watch the Magpies pull off a superb result and chronicled his day in this here video:
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