Experienced striker Marc Richards scored his second goal in five days as Chesterfield clinched their third npower League Two win in a week, 1-0 at struggling Plymouth.
The 30-year-old former Port Vale forward smashed the winner in the 66th minute after Jack Lester chested down a cross from fellow substitute Luis Boa Morte.
The introduction of the former Portugese international at half time had the desired effect as he sent a 30-yard shot just wide and then missed the target with a brilliant shot on the spin before setting up the winner.
Plymouth should have made the most of their first half advantage, when they had a shot cleared off the line and hit the bar.
Alex MacDonald sparked the best Argyle spell in the 35th minute, forcing visiting keeper Tommy Lee to go full stretch to keep out a low drive.
From the resultant corner Richards headed off the line as home central defender Curtis Nelson sent his header towards goal.
Seconds later, with Plymouth piling on the pressure, Andres Gurrieri's goal-bound shot was headed up and on to the bar by Spireites skipper Sam Hird.