Two-time world champion Mark Williams, bidding to become the oldest snooker world champion since fellow Welshman Ray Reardon 40 years ago, trails Barry Hawkins 5-3 in his semi-final heading into Friday’s second session. At 43, Williams would be two years younger than Reardon, who won the last of his six titles aged 45 in 1978, but he faces a tough battle against 2013 finalist Hawkins, who outclassed Chinese superstar Ding Junhui in the quarter-finals. Williams, who won the last of his two world titles in 2003, trailed 3-1 at one stage but then rallied and had the last laugh with a sparkling break of 110 to remain firmly in contention in the best of 33 frames encounter. Scotsman John Higgins, a four-time world champion, showed little sign of fatigue after a nerve-wracking 13-12 quarter-final victory over Judd Trump as he took a 5-3 lead against Englishman Kyren Williams. Higgins, who lost to Mark Selby in last year’s final, stormed into a 4-1 lead before Wilson pulled back two frames but the Englishman making his first appearance in the last four made a cardinal error in the final frame to allow his 42-year-old opponent to take a two-frame advantage into Friday’s second session. The semi-finals will come to a conclusion on Saturday with the final played over Sunday and Monday.