Stephen Duke-McKenna fired in the opener from the edge of the box on 70 minutes.
Armani Little then added a second from the penalty spot 10 minutes later after he was fouled by Jim Kellermann.
The Spireites remain seventh for now, but could slip out of the play-off positions if Dagenham and Redbridge win at Solihull Moors later today.
But, unless they suddenly start clicking, it is hard to see Chesterfield making any progress in the play-offs if they did qualify.
Top of the league in January, it has been a disastrous second-half of the season. There are valid reasons, but the fall from the top has been bigger than anyone could have expected.
Paul Cook made three changes from the defeat to Stockport County on Monday with Alex Whittle, Joe Quigley and Akwasi Asante replacing Calvin Miller, Jim Kellermann and Tom Denton.
The first-half was a tough watch from a Chesterfield point of view. It was scrappy, disjointed and littered with mistakes. They could not keep possession for any sustained periods and that resulted in offering nothing in the final third.
If you didn’t know the context of what was on the line for each team, you would have thought it was the Spireites who had nothing to play for and it was Torquay who were aiming for the play-offs.
It wasn’t a total surprise, the Blues have been playing like this for a while, but it didn’t make it any easier to stomach.
Torquay played on the front foot, won a lot of second balls, had a real intensity in their attacking play and should have led at half-time.
Scott Loach parried Asa Hall’s low, driven shot from distance and he later made a smart reaction save to keep out Danny Wright’s clever flick at the near post from a corner.
The only sniff of a chance for Town came when Liam Mandeville pounced on a mistake in the home defense but his cut-back for Akwasi Asante, who was lurking near the penalty spot, was intercepted.
Oyleke blasted wide from distance on the stroke of half-time, but other than that, there was not much to cheer for the 900 traveling Spireites who had filled the away end with color and enthusiasm.
The only thing Chesterfield will have been happy with at half-time was the scoreline.
Cook tried to change things at the break with Kellermann replacing Oyeleke.
And there was a second change 10 minutes into the second-half when Danny Rowe replaced Asante, who hobbled off.
There were some early shoots of recovery as Jamie Grimes headed wide from a corner and then Jeff King delivered a wonderful, inviting low cross which was begging to be tapped home but nobody had gambled.
But, in the end, it was false hope.
With 20 minutes remaining, Duke-McKenna fired into the bottom corner after cutting inside on his left foot. The only shock was that it had taken that long for the hosts to take the lead.
Rowe almost announced his return with a classic blockbuster from distance which clipped the outside of the post.
But ten minutes later it was game over, if it wasn’t already, as Little doubled the hosts’ lead from the penalty spot, which may have been a controversial decision.
That was the cue for Spireites fans to head for the exits – and you couldn’t blame them.
Chesterfield: (3-4-1-2) Loach; Williams, Gunning, Grimes; King, Weston (Khan, 82), Oyeleke (Kellermann, 46), Whittle; Mandeville; Asante (Rowe, 55), Quigley.
Unused subs: Maguire, Denton.