Mark Williams (left) and John Higgins have won seven world titles between them [PA Media] Four-time world champion John Higgins took advantage of some mistakes from Mark Williams to lead 5-3 after the first session of their World Championship quarter-final. This tie features two of the sport's all-time greats and two thirds of snooker's legendary 'Class of 92' trio, which also includes Ronnie O'Sullivan. Williams, 50, became the oldest man to reach the last eight at the Crucible since Steve Davis did so at the age of 52 in 2010, while Higgins turns 50 on 18 May, 13 days after this tournament's final. Both men received a fantastic standing ovation when introduced to the crowd, with the spectators then treated to some high-quality snooker. A break of 69 took Higgins ahead, but Williams should have levelled, only for the Scot to snatch the frame on the black following a run of 65. An effort of 72 gave the Welshman his first frame, only for him to miss a brown in the fourth frame, and that proved costly as Higgins took the first of three frames in a row. Being 5-1 ahead, Higgins would have hoped to stretch his lead, but Williams responded well with breaks of 104 and 59. The best-of-25 match resumes at 19:00 BST and will be played to a finish on Wednesday from at 10:00 BST. Zhao in control against Wakelin In the morning session's other match, China's Zhao Xintong took control of his quarter-final tie with Chris Wakelin. The Englishman, who came through two qualifying rounds to get to the Crucible, eliminated 2010 world champion Neil Robertson in the first round of the main tournament and then defeated former world number one Mark Allen in the last 16. Wakelin, 33, made a break of 93 to take the opening frame, but 28-year-old Zhao then dominated to win six in a row, although Wakelin took the last to trail 6-2 before that match resumes at 19:00 BST. Zhao, a former UK Championship winner, was one of 10 players from China to receive a ban in a match-fixing scandal. He did not directly throw a match, but accepted charges of being a party to another player fixing two matches and betting on matches himself. Zhao - who served a 20-month ban for those offences - is the only of the 10 players sanctioned in the scandal to have returned to action. As a result of the ban, he lost his place on the World Snooker Tour, although he has already ensured he will be back on the tour full-time next season. For this tournament, he is officially classed as an amateur and this is his seventh match of the competition after he had to fight through four qualifying rounds.