They were made to pay when on-loan Chelsea youngster Bamford received the ball on the right, stepped inside and curled a wonderful left-foot shot home off the underside of the bar for his fifth goal in six games.
The win takes Steve McClaren's side ahead of QPR and within two points of second-placed Burnley.
Wigan jumped to seventh with a 2-0 home win against relegation-haunted Barnsley but saw midfielder Ben Watson suffer a serious injury in the first half.
Watson came off worst in a challenge with Martin Woods, sparking fears of a season-ending second broken leg in 15 months.
Barnsley played their part and had chances of their own but are now just one point above bottom club Yeovil, who drew 0-0 with Watford.
The Glovers had the best chances of a drab encounter, Joe Edwards wasting a clear-cut opportunity while Hornets goalkeeper Manuel Almunia denied James Hayter and Joe Ralls.
- Sports & Recreation
- Michail Antonio
- Steve McClaren