Ali Carter has fought back to level the early stages of the Betfred.com World Snooker Championship after a blistering start from opponent Ronnie O'Sullivan.
The three-time champion captured a nervy opening frame, with the first pot not coming until 12 minutes of sparring.
O'Sullivan then delivered a typically impressive century break of 117 to open up a two-frame lead before fellow Essexman Carter responded with a break of 84 in the next.
Carter went on to level the match in frame four of a potential 35.
O'Sullivan defeated Carter 18-8 in his last final appearance at the Crucible in 2008.
