World Snooker Championship 2018: Ronnie O'Sullivan trails Ali Carter 9-7
|2018 World Championship|
|Venue: Crucible Theatre, Sheffield Dates: 21 April - 7 May|
|Coverage: Watch live across BBC One, BBC Two, BBC Red Button, Connected TV, the BBC Sport website and mobile app.|
Five-time champion Ronnie O'Sullivan won four of the day's last five frames to trail Ali Carter 9-7 in their World Championship second-round match.
Carter, who has lost all four of their meetings at the Crucible - including the 2008 and 2012 finals, won five frames in a row to lead 8-3.
But O'Sullivan fought back, capped by a 105 break in the last frame of the day.
Mark Allen earlier became the first player to reach the last eight by beating Joe Perry 13-8.
Rapid breaks of 121 and 61 saw O'Sullivan move 2-1 ahead against Carter, but the world number 15 made it 2-2, and a stylish 115 clearance put him 3-2 up.
O'Sullivan levelled with an effortless 96, but his fellow Englishman won the last two frames of the session to take a 5-3 advantage.
The evening began with O'Sullivan, winner of five ranking titles this season, in uncharacteristically subdued fashion.
Carter gained a five-frame lead with an assured 72 after crowd favourite O'Sullivan missed a black off its spot.
O'Sullivan secured the final frame before the mid-session interval and began to display customary touches of brilliance with another run of 55.
Carter won the 14th with a 51 after O'Sullivan's 54 was ended by an unfortunate kick on a red, but 'The Rocket' responded in style with runs of 79 and 105.
Allen surge sends out Perry
World number 22 Perry fought back from 5-3 down against Allen to leave their last-16 match delicately poised at 8-8 after their second session.
But Northern Irishman Allen, who has failed to progress beyond the second round in Sheffield in the past six years, knocked in a 133 in the second frame of the evening and added a 72 before winning the match in style with a 122.
History repeats as Lyu hangs on against Hawkins
Chinese qualifier Lyu Haotian once again staged a fine fightback to stay in the hunt at 9-7 behind against world number six Barry Hawkins.
The 20-year-old Crucible debutant trailed 5-3 overnight, having been 4-0 and 5-1 down.
Hawkins, the 2013 runner-up, took the first three frames with breaks of 124, 83 and 61 for an 8-3 lead, but Lyu was then in sparkling form, rattling off scores of 125, 72, 79 and 60 to reduce the gap to 8-7.
Both men failed to take clear openings in a rare sloppy final frame, but the 38-year-old Kent-based left-hander, a Crucible semi-finalist in three of the past four years, held his nerve to maintain his two-frame advantage.
The other afternoon match saw Kettering's world number nine Kyren Wilson earn a 5-3 overnight lead over Welsh qualifier Jamie Jones.
World number 51 Jones, 30, moved 2-1 ahead, but three consecutive 50s from 26-year-old Wilson put him in command and the pair shared the last two frames of the session.
Both matches play to a finish on Saturday.
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