Lester's clever finish in the first half was enough to clinch the points against a Torquay side who created few clear openings.
Both teams had played some neat football without really threatening until the 28th minute when a quality ball in from Drew Talbot was matched by Lester's skilful volley past Scott Bevan.
Kevin Nicholson brought a good save from Tommy Lee with a 25-yard free-kick but it was Chesterfield who looked more likely to score with Jordan Bowery twice going close early in the second half.
Lee denied Chris Zebroski with his legs in the 69th minute but Bowery wasted a good chance to settle the game when he broke away but could not beat Bevan.
Source: PA
Source: PA