Image source, Getty Images
Kyren Wilson beat Jak Jones in last year's final to become world champion for the first time
Phil Cartwright
BBC Sport journalist
Halo World Championship
Venue: Crucible Theatre, Sheffield Dates: 19 April to 5 May
Coverage: Watch live on BBC TV, BBC iPlayer, BBC Sport website and app; live text coverage of selected matches; updates on BBC Radio 5 Live
Reigning champion Kyren Wilson holds a 6-3 lead over Lei Peifan in the first match of his world title defence at the Crucible Theatre in Sheffield.
The world number two twice missed blacks off the spot in the second frame as Crucible debutant Lei, 21, went 2-0 in front.
The 33-year-old Englishman recovered to win the next six frames in succession, making a 136 break in the eighth to add to three earlier half-centuries.
But Chinese qualifier Lei pinched the final frame of the session, after Wilson missed a pink trying to get position on a tricky last red, to give himself hope of a comeback.
Their best-of-19-frames contest will be played to a finish from 19:00 BST.
Should he progress to round two, Wilson will face either Jak Jones - the player he beat in the 2024 final - or former UK Championship winner Zhao Xintong.
Wilson is aiming to break what has become known as the 'Crucible curse' - since the World Championship moved to Sheffield in 1977, no first-time winner has retained the title the following year.
World number 14 Xiao Guodong is in control of the other match to be played on Saturday morning.
Xiao and Matthew Selt made two century breaks apiece in the opening nine frames, but the Chinese player will take a 7-2 advantage into Sunday's concluding session.
Former champions Neil Robertson and Mark Williams get their Crucible campaigns under way in Saturday's afternoon session (14:30).
Schedule: Saturday, 19 April
10:00
Kyren Wilson 6-3 Lei Peifan
Xiao Guodong 7-2 Matthew Selt
14:30
Neil Robertson v Chris Wakelin
Mark Williams v Wu Yize
19:00
Kyren Wilson 6-3 Lei Peifan*
Barry Hawkins v Hossein Vafaei
*match to be played to a finish