Celtic's 4-0 win over Dundee United on Saturday has been marred by controversy after former referee Bobby Madden slammed the handball decision that allowed Camilo Duran's second goal. Madden, a former Premiership and English FA whistler, insists that the goal should have been chalked off for a handball. The Colombian striker converted from close range after fellow new recruit Kasper Hogh saw an initial effort blocked. Replay showed that the ball had struck Denmark star Hogh's arm seconds before the goal but following a short VAR review, on-field referee Steven McLean was instructed to award the goal. Madden referenced two other examples in high-profile games where goals were overturned because of a handball. He pointed to a game between Switzerland and Spain, where a goal was scored after an accidental handball by the hand of a teammate long before the goal was scored. UEFA were clear that this goal should be disallowed. Madden also mentioned a game between Inter Milan and Liverpool in the Champions League last season, where a teammate's header onto the arm of another player before the ball went to the scorer was deemed a handball. UEFA were clear that this goal should also be disallowed. The challenge is understanding why there are different interpretations of the handball rule. Celtic are currently 3 points behind leaders Heart of Midlothian in the title race, with 59 goals scored and 35 conceded this season. They are on a 5-game winning run, with their last result being a 3-1 win over Heart of Midlothian on May 16.