Bradford's unbeaten start to the season continued when a Billy Clarke goal sealed a deserved 1-0 win at Chesterfield.
The visitors dominated in front of nearly 2,000 Bantams fans and should have won the game comfortably but Chesterfield rarely threatened.
Bradford finally made their possession count in the 26th minute when a short corner was picked up by Clarke who drove a shot from the left-hand edge of the area into the roof of the net.
Chesterfield were denied an equaliser in the 31st minute when Colin Doyle made a superb save to turn over a 25-yard free-kick from Kristian Dennis.
Bradford went close to a second in the 42nd minute after Jordy Hiwula broke through on the left but Ryan Fulton blocked his low shot.
Fulton rescued Chesterfield again in the 47th minute with a brilliant reaction save from a Hiwula flick and the visitors had another chance when Timothee Dieng put James Meredith in but he dragged his shot wide.
Mark Marshall fired wide from a good position and Meredith had another chance in stoppage time.