Fergal O'Brien had to show nerves of steel as he battled into the last 32 of the Welsh Open in Newport.

The Dubliner had moved within one frame of victory against Thepchaiya Un-Nooh but the Thai player fought back to move the brink of progress.

Trailing by 28 in the last frame, O'Brien needed to clear the remaining balls to snatch the victory, and that's exactly what he did with a break of 33.

Next up is a date with Jimmy Robertson.

O'Brien, who is set to turn 50 next week, is battling to stay in the tour. Currently 51st in the one-year ranking list, only the top-64 players are guaranteed a card for next season.

World No 11 Mark Allen cruised into the next round with a 4-0 win over Ukrainian teenager Iulian Boiko.

Earlier, Ronnie O'Sullivan put his shock defeat in the European Masters final behind him with a comfortable 4-0 win over James Cahill – before casting doubt on his ambitions for another World Championship title.

Elsewhere during Tuesday's early matches at Celtic Manor, home favourite Mark Williams was edged out 4-3 by Norwegian Kurt Maflin while Australian Neil Robertson made two century breaks as he coasted past Hammad Miah 4-1.

There were also first-round victories for China’s Ding Junhui, Joe Perry, Scott Donaldson and Ali Carter, who chalked up a 4-1 win over Hong Kong’s Ng On Yee, the first woman to compete in the event.

In Tuesday’s evening session, world number three Judd Trump scored a break of 120 in the final frame of his convincing 4-1 win over Craig Steadman to reach the last 32.

Five-time winner John Higgins hit a couple of centuries as he progressed 4-0 against Iran veteran Soheil Vahedi, with Matthew Selt and Jack Lisowski also coming through their late matches.