Anthony McGill missed a shot at a maximum break at the world snooker championship, but clawed back a three-frame deficit against the defending champion Ronnie O’Sullivan. Their second-round, best-of-25 match is finely poised at 4-4 after the first session at the Crucible. McGill left his 13th black tottering over the bottom pocket in the seventh frame as he aimed to become only the eighth different player to achieve a fabled 147 at the famous Sheffield venue. Both players set the tone for a high-quality session from the start, with O’Sullivan delivering a quickfire 81 to win the opening frame and McGill responding with a 79 to draw level. Consecutive centuries of 105 and 138 saw the six-times champion O’Sullivan cruise into a 3-1 lead and despite missing two relatively simple blacks in the fifth frame, he was not punished and a 49 to pink saw him extend his lead to 4-1. McGill was then handed a lifeline in the next as O’Sullivan over-screwed a red, allowing the Scot to cut the gap to two. The 30-year-old then found himself with a chance at a maximum, and looked superbly before running aground on 97 when he left the black in the jaws of the pocket. Last year’s semi-finalist, who was a final-frame loss away from facing O’Sullivan in the final, shrugged off the disappointment with a break of 40 in the final frame of the session to secure parity. The three-times champion Mark Selby grabbed the two frames he needed to complete a 10-1 rout of last year’s surprise quarter-finalist Kurt Maflin. Selby, the No 4 seed, was in merciless form throughout the match, firing two centuries and six further breaks over 50 as he set up a highly anticipated second round meeting with Mark Allen, who looked in fine form in breezing past Lyu Haotian 10-2. Selby said: “I came into the tournament feeling confident about my game and it’s got to be up there – especially doing it in the first round of a world championship, because it’s always difficult to get over that first hurdle.” Former winner Shaun Murphy came through a tricky first-round encounter, coming from behind to defeat the veteran qualifier Mark Davis 10-7. The 2005 champion started the final session 5-4 down but gradually turned the match in his favour and a final flourish of 131 saw him over the line. “I stole two frames I had no right to win and that energised me a bit and gave me a kick up the backside,” said Murphy, the No 7 seed, who plays the Masters champion, Yan Bingtao, next. “Finishing last night’s session with a century gave me good vibes overnight and set the tone.” Breaks of 135 and 76 enabled Neil Robertson to establish a 5-3 advantage over Jack Lisowski at the end of the first session of their second-round clash. Robertson looked out of sorts for much of the session and Lisowski missed a number of chances to make him pay, before the Australian came good to end the evening on top.