Former Celtic player Oh Hyeon-Gyu came back to haunt Rangers as his goal secured Genk a 1-0 win in their Europa League opener at Ibrox. The pressure continues to build on Russell Martin, whose side also saw Mohamed Diomande sent off in the first half, giving the hosts a mountain to climb. Rangers started well, with John Souttar coming closest to an opener in the 17th minute as his thumping header was brilliantly cleared off the line by an acrobatic Bryan Heynen.