Marc Richards scored the decisive goal against Plymouth to help Chesterfield pick up their third win in a week.
The home side forced Richards to head Curtis Nelson's header off the line in the first half, while Andres Gurrieri struck the crossbar.
The Spireites brought on Luis Boa Morte at half-time and the Portuguese soon went close with two long-range efforts.
And it was his cross which was chested down by Jack Lester, allowing Richards to smash in the winner.
VIEWS FROM THE DRESSING ROOM
Plymouth Argyle manager Carl Fletcher told BBC Radio Devon:
"I end up sounding like a broken record but again we've dominated in every sense, but it just didn't bounce for us today. All the hard work we're putting in just isn't paying off.
"The pleasing thing is that the lads are playing well and working hard for each other. The downside is we're just not getting the results.
"We don't just smash the ball around and hope something goes our way.
"We've been working hard on getting on the front foot and keep teams defending when we can and I thought we did that well today.
"(On the penalty decision) I think the linesman was that side so I'm not sure why he's not seen it. It's just the way it's going right now, we must have driven past a few black cats or something."
Chesterfield manager Paul Cook tells BBC Radio Sheffield:
"We're delighted again. Three points for any team on any day is a great achievement.
"Level of performance is important and today our level of performance was through commitment and effort.
"We weren't good in the game. We never moved the ball as well as we did the other night against Cheltenham.
"But we certainly had no lack of commitment and effort.
"Plymouth were good value for a point. We must accept that but that happens in football."