Ryan Harley at the double as Exeter City win at Plymouth

League Two leaders Plymouth saw their three-match winning run come to an end after going down 2-1 to Devon rivals Exeter in front of 14,008 at Home Park.Midfielder Ryan Harley was the chief architect as he scored a pair of goals to put City 2-0 up at half time.The City playmaker's 30th-minute opener came after Plymouth right-back Kelvin Mellor fouled Exeter winger David Wheeler in the six-yard box.Harley picked his spot to put the ball in the corner and out of the reach of goalkeeper Christian Walton, making his Plymouth debut following his midweek loan switch from Brighton & Hove Albion.Harley then found the same corner with a superb 18-yard strike after 39 minutes as he waltzed through the home defence.On-loan Bolton midfielder Oscar Threkeld hauled Plymouth back into the match after an hour, firing home from the edge of the box.Plymouth playmaker Graham Carey came close to levelling with a soaring 76th-minute volley which flew inches over.