The five-time world champion trailed Lines 2-1 before bouncing back with three frames in a row to advance.

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O’Sullivan’s biggest break was 87 in the fifth frame, and he admitted he felt fortunate to reach the second round having felt like he was “playing blindfolded”.

“I’m just happy to still be in this tournament. I thought I was going to get beat tonight," he told Eurosport.

Watch O'Sullivan's bizarre break

“I was struggling with the table, the pace of it, I just overhit it. I played on a club table yesterday for about two hours and that was the worst thing I’ve done.

“This felt like an ice skating rink, just trying to control the white, and then he started to get confident because I wasn’t punishing him.

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“I gradually got a bit more used to it, you have to change the technique as you go along and it started to feel a little bit more normal towards the end out there… But it was like playing blindfolded.”

O’Sullivan, losing finalist in the Northern Ireland Open last year, faces Lei Peifan in the next round in Belfast.

Champion of Champions Neil Robertson is out, losing 4-3 to Mark Joyce, who put together runs of 52, 137 and 114 to progress against the out-of-sorts Australian.

Elsewhere, Judd Trump fended off a spirited fightback from James Cahill, beating the world number 113 4-3.

Cahill, who defeated O’Sullivan at the first-round stage at the World Championships back in May, fought back from 3-0 down to send the match to a deciding frame.

Watch the Northern Ireland Open LIVE on Eurosport and Eurosport Player

However, Trump, who had put together three ton-plus runs - 106, 122 and 111 - to open a three-frame lead, compiled a 75 to seal progression to round two, where he will meet Anda Zhang.

Earlier, Stuart Bingham made a sixth 147 of his career en route to a 4-3 victory over Lu Ning.

Watch in full: Stuart Bingham’s 147 at the Northern Ireland Open

The 2015 world champion added breaks of 58 and 57 to the opening-frame 147 to put himself to within one frame of the second round.

However, Lu, ranked 60th in the world, levelled the first-round match on the back of runs of 70 and 78 but Bingham, the 2018 English Open winner, ground out a tactical final frame to progress.

NORTHERN IRISH OPEN ROUND ONE RESULTS

  • Joe Perry 4 – 2 Zhao Xintong
  • Fergal O'Brien 4- 2 Fan Zhengyi
  • Joe O'Connor 4 – 2 Brandon Sargeant
  • Michael Holt 4 – 2 Michael White
  • Stuart Carrington 4 – 1 John Astley
  • Ronnie O'Sullivan 4 – 2 Oliver Lines
  • Kyren Wilson 4 – 0 Alan McManus
  • Zhou Yuelong 4- 0 David Grace
  • Ricky Walden 4- 0 Alex Borg
  • Sohail Vahedi 4- 3 Jack Lisowski
  • Yuan Sijun 4 – 2 Gary Wilson
  • Matthew Selt 4 – 2 Daniel Wells
  • Mark Allen 4 – 1 Sam Craigie
  • Peter Ebdon 4 – 2 Jimmy White
  • Ben Woollaston 4 – 2 Jamie Clarke
  • Stuart Bingham 4 – 3 Lu Ning
  • Kacper Filipiak 4 – 3 Riley Parsons
  • Martin O'Donnell 4 – 3 Lee Walker
  • Chen Zifan 4 – 2 Patrick Wallace
  • Judd Trump 4 – 3 James Cahill
  • Luo Honghao 4 – 2 Dominic Dale
  • Sam Baird 4 – 2 Nigel Bond
  • Scott Donaldson 4 – 1 Alfie Burden
  • Craig Steadman 4 – 1 Bai Langning
  • Jamie O'Neill 4 - 2 Akani Songsermsawad
  • Jimmy Robertson 4 – 3 Igor Figueiredo
  • Lei Peifan 4 – 2 Louis Heathcote
  • Billy Joe Castle 4 – 3 Noppon Saengkham
  • Graeme Dott 4 – 2 Duane Jones
  • Ross Bulman 4 - 1 Zhang Jiankang
  • Liang Wenbo 4 – 1 Kurt Maflin
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