Derby County boss Paul Warne has claimed he is “disappointed” by a late refereeing decision that went against his side in the defeat to Stoke City. The Rams were unable to extend their four-match unbeaten run in the Championship when they made the short trip to Staffordshire on Saturday in a difficult away performance. A poor first-half showing saw Tom Cannon put the Potters in the lead, following a penalty call on the striker after being felled by Jacob Widell Zetterstrom. Derby responded after the break with a double substitution but it was a slice of luck that went their way as Ben Gibson h…