Scotland\'s Ricky Burns thwarted Englishman Kevin Mitchell\'s bid to relieve him of his WBO world lightweight title on Saturday with a convincing fourth round stoppage. The 29-year-old had Mitchell on the canvas twice in the fourth round before the referee stepped in to put the English fighter out of his misery. \"The whole build-up went perfectly. I\'ve been feeling so much stronger. My confidence is there too, but I felt so much stronger,\" said Burns. \"I said I\'ll try and suss him out in the first round. When I had him on the ropes I wanted to rough him up and it worked.\"