JAMIE Cope crashed out of the Northern Ireland Trophy in Belfast last night after a bout of the shakes.

The Longton cueman branded himself "useless" after being thumped 5-2 by Joe Perry, a World Championship semi-finalist last season.

And with his disappointing defeat, Cope missed out on a dream last 16 showdown with world champion and world number one Ronnie O'Sullivan, who was forced to dig deep from 4-2 down to beat Irishman Ken Doherty 5-4 .

"There was only one problem, I couldn't stop shaking. I can't play snooker when I've got the shakes," revealed world number 19 Cope.

"I couldn't relax for some reason, I was useless. I felt a bit nervous for some reason, I couldn't get through the ball at all.

"I was just jabbing at every shot. It happens to me now and again, maybe a couple of times a year. I don't know what the problem is."

Cope, a 5-4 victor over David Gray earlier in the week, did manage to pocket breaks of 50 and 96 at the Waterfront Hall.

But world number 12 Perry impressed with runs of 79, 80, 71 and 96 to progress.

That leaves Trent Vale's Dave Harold as Stoke-on-Trent's last Irish hope. The former Asian Open winner locks horns with Stephen Lee, last season's Masters runner-up, in the last 16 today (1pm).

Victory for the world number 28 would yield a quarter-final meeting with either defending champion Stephen Maguire or Alan McManus tomorrow.

"I'm looking forward to the match. I've got two wins under my belt, but the added incentive is to get into the quarter-finals," said Harold.

"Stephen's a very good player, but he's fallen down the rankings, so the pressure will be on him.

"I'd like to think I could play better than the last round (a 5-3 victory over former world champion Graeme Dott), I didn't really perform great in that match."

O'Sullivan, meanwhile, spoke of his relief to have overcome Doherty.

"I could have lost that match, Ken is the type of player who will not give you many opportunities.

"You're not going to win lots of matches from 4-2 down, so I'm pleased I got through."I had to make something happen. I did which is very pleasing," added O'Sullivan, who compiled runs of 110, 83, 74 and 85.

"I'm always really focused. It was a great atmosphere out there. He had a lot of support from the Irish supporters, which you'd expect.

"But I also had good support out there, so it made for a good atmosphere.

"You enjoy it when the atmosphere is good. A big crowd helps you concentrate."

In other action, two-time world champion John Higgins made it through to the last 16.

The world number five beat David Gilbert, a qualifier from Derbyshire, 5-2 thanks to breaks of 97, 49, 81, 47, 56 and 54.

Welshman Ryan Day, twice a ranking event finalist, beat Preston's Stuart Pettman 5-4, but nearly lost as his opponent came back from 4-1 down to force a decider.

Yesterday's results: Mark Selby (Eng) beat Andrew Higginson (Eng) 5-1; Ali Carter (Eng) beat Rory McLeod (Eng) 5-1; Barry Hawkins (Eng) beat Marco Fu (Hong Kong) 5-2; John Higgins (Sco) beat Dave Gilbert (Eng) 5-2; Joe Perry (Eng) beat JAMIE COPE (Eng) 5-2; Ryan Day (Wal) beat Stuart Pettman (Eng) 5-4; Mark Davis (Eng) beat Ding Junhui (Chi) 5-4; Ronnie O'Sullivan (Eng) beat Ken Doherty (Ire) 5-4.