Reading had won nine of their previous 11 games against Derby but came into the match with seven first-teamers missing, which meant a first league start for 19-year-old Jordan Obita.
The Royals had not conceded in 285 minutes of Championship football but their defence was almost breached in the eighth minute when Johnny Russell got in on the left and Alex McCarthy could only push out his low shot but Craig Bryson could not turn in the rebound.
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Wednesday morning's weather for the east of the region
Wednesday morning's weather for the west of the region
The first of 1,400 new commuter train carriages for the south has just arrived from Germany.