Windass, who has now notched eight this season, was the focus of transfer speculation towards the end of the transfer window as Wigan looked to poach the 36 year old.
But Windass confirmed his commitment to the Bantams by scoring the first in a 2-0 win.
Ben Muirhead, who was a constant menace to the Chesterfield defence, created the opening with a strong run and low cross. The ball came to Windass who had his back to goal but he managed to swivel and turn the ball into the corner of the net.
There was a sense of relief in the striker's celebration as he had been guilty of missing the game's best chance two minutes after the restart.
Reuben Hazell's weak back pass put the striker clean through on goal, but it was almost as if he had too much time as he hesitated before firing his shot straight at Barry Roche who somehow managed to recover and tip the follow-up effort around the post.
From the resulting corner Andy Cooke came close to scoring his first of the season, but Hazell made up for his earlier mistake with a desperate sliding clearance of the line.
Just as the home fans began get frustrated, Windass put them in front and influential midfielder Marc Bridge-Wilkinson calmed the nerves with a well-taken second with nine minutes left.
Again Windass was involved as he knocked the ball into Bridge-Wilkinson's path and City's playmaker fired into the coroner from the edge of the box for his second of the season.
The win was a welcome relief for City who had lost their pervious two games but they struggled to create any real chances during a tepid first half.
It was Windass who was again guilty of missing the best chance went he headed Muirhead's excellent centre over the bar.
Both teams were reduced to shots from distance and although City had more of the ball Chesterfield looked dangerous on the break.
City upped the tempo in the second half and dominated possession but until Windass struck they had struggled to find that killer touch.
Veteran striker Steve Claridge came off the bench and should have made it three after he was put through by Windass but the former Millwall manager scuffed his shot harmlessly wide.