Will Swan's first-half goal helped Crawley beat Rotherham 1-0 at the Broadfield Stadium and heap more pressure on their former boss Steve Evans.
Swan struck in the 21st minute to condemn the Millers to a fourth defeat in five League One games.
Crawley worked hard for their victory throughout in the wind and rain as Rotherham struggled to create many clear-cut chances.
The Red Devils have not scored inside the first 15 minutes of any league game so far this season although forward Ade Adeyemo came close early on when he drove narrowly over from the edge of the area.
At the other end defender Joy Mukena made a vital block when the recalled Jonson Clarke-Harris directed a point-blank header from Hakeem Odoffin's cross.
Crawley went in front when Toby Mullarkey picked out Swan with an accurate cross and the former Mansfield forward steered the ball home from close range, giving recalled keeper Dillon Phillips no chance.
The hosts bossed the first half and the Millers rarely threatened, although Nottingham Forest loanee Esapa Osong forced keeper Jojo Wollacott to make a scrambling save just before the interval.
Rotherham, with the wind behind them, had more possession at the start of the second half and substitute Alex MacDonald put a free-kick only just wide.
Crawley substitute Tyreece John-Jules threatened with virtually his first touch, his shot on the turn saved by Phillips.
Substitute Rafiq Khaleel should have extended Crawley's lead late on but wastefully shot over after being set up by Jeremy Kelly.
The Millers had a chance to steal a point right at the death, but substitute Ciaran McGuckin was unable to connect at the far post.