Drew Talbot's long-range strike gave Chesterfield a 1-0 victory at Notts County - their third in four games - to maintain their play-off push.
The 22-year-old, who joined on loan from Luton last week, latched onto a long pass and cut inside to lash the ball over goalkeeper Josh Lillis and into the far corner.
The goal, eight minutes before half-time, came very much against the run of play as County had just missed two golden opportunities - Tommy Lee saving from Jamie Forrester and Mike Edwards somehow missing the target from five yards.
Chesterfield shut up shop in the second half and defended stubbornly, holding on for the three points despite seeing Danny Hall sent off late on for a second yellow card.
In a feisty derby atmosphere both sides took a while to settle, but County gradually got on top with Michael Johnson heading over from a corner.
Notts County goalkeeper Lillis had to be alert to clear from two balls over the top before Adam Nowland forced a fine save from Chesterfield keeper Lee. Nowland combined with Forrester to fire a goalbound shot which was tipped over.