Snooker: Ronnie O'Sullivan eyes Crucible's big prize after keeping Ali Carter at arm's length

Champion leads 9-7 in last-16 tie as he aims to become first to retain Crucible title since 1996

Ronnie O'Sullivan at the table in his second round match against Ali Carter during the Betfair World Championships at the Crucible, Sheffield (PA)

Defending champion Ronnie O'Sullivan remains on course for a successful title-defence here in Sheffield despite being pushed hard by Ali Carter in the penultimate session of their last-16 clash.

The "Rocket" returns tonight with a welcome 9-7 lead after Carter, his fellow Essex professional, forced the pace having trailed 5-3 overnight.

But despite Carter's spirited attempt to close the gap on O'Sullivan, it is the four-time world champion who is favourite to progress to the last eight.

And with five former world champions having already fallen by the wayside, O'Sullivan will fancy his chances of becoming the first player since Stephen Hendry, in 1996, to make a successful Crucible title-defence. O'Sullivan started with an 86 break to extend his lead, but Carter hit back with runs of 73 and 87.

But a fine 105 break – O'Sullivan's third century of the tournament – saw him edge 7-5 ahead at the interval. A confident Carter rallied following the resumption and pocketed breaks of 63 and 46 to level matters.

But O'Sullivan, who had looked decidedly shaky during the afternoon, held his nerve to restore a two-frame lead thanks to breaks of 73 and 86.

Victory for either player would yield a quarter-final meeting with either Stuart Bingham, from Basildon, or Hastings professional Mark Davis.

Meanwhile, Judd Trump, snooker's latest sensation, believes some players are jealous of his meteoric rise. The player nicknamed the "Juddernaut" has taken the sport by storm over the past two years having powered to three ranking titles and reached a string of finals.

The 23-year-old has pocketed close to £1m in prize-money and lucrative sponsorship deals, and it has not been to the liking of some of his fellow professionals. And so the Bristolian is determined to stay focused at this year's event. "I feel as though some people don't like the limelight I get," said Trump. "Some players say things about me, but it's the only way they can get some limelight. I just let my snooker do the talking."

Former world champion Neil Robertson accused Trump of being "fake", while other critics have privately voiced their concerns that the left-hander has become too big for his boots after his breakthrough success in reaching the 2011 world final.

Shaun Murphy, the 2005 world champion, suggested Trump's over-confidence this season had increased the pressure on him to be successful. "Having that air about you that you will win and it is just a question of turning up, that can put undue pressure on yourself," said Murphy.

"I'm sure he'd be the first to admit that, but he's had massive success over the last few years and ripped through the field at times. The way he scores it can be like a knife through butter."

But Trump, who faces Murphy in the Crucible quarter-finals tomorrow, is determined to silence his rivals and win the world title for the first time. "Shaun's got his own opinions, but I'm just concentrating on my own game," added Trump.

"Shaun doesn't know me so he wouldn't know what I do. I just go in with the same attitude towards every tournament. Whatever tournament I enter I'm fully prepared to win."

In yesterday's other match, Ding Junhui produced a spirited comeback to keep his world title hopes alive.

Ding, a former Masters and UK champion, resumed 6-2 down against Mark King after the opening session of their second-round match.

But the world No 9 hit back with runs of 59, 98, 74, 81 and 103 in battling back to lead 9-7. He returns today needing four frames for victory.