Left-back Cucurella won back possession in 54 minutes to allow the £30million midfielder to slalom through the Danish defence before scoring with his left foot and ending the chance of a shock defeat.
After winning the first leg 2-1, this was Chelsea's eighth consecutive win in the third-tier competition thanks to an improved second-half performance.
Blues boss Maresca said: "It's important to reach the quarter-finals. Now the target is the next step whic...