Former world champions Stephen Hendry, Shaun Murphy, Peter Ebdon and Graham Dott all departed the Northern Ireland Trophy in the second round on Tuesday.
Hendry was thrashed 5-1 by Stephen Lee and Murphy lost 5-2 to Mark Williams.
Ebdon was humbled 5-0 by Liang Wenbo and Dott let slip a 3-1 lead against Dave Harold, but defending champion Stephen Maguire beat Michael Holt 5-1.
"It was always going to be tough but I didn't expect a 5-1," said Maguire, who will now play Alan McManus.
The Scot eased past England's Mark King 5-3, Ian McCulloch beat Neil Robertson 5-2 and Mark Allen edged past Dominic Dale 5-4.
Ebdon, whose Chinese opponent came through the qualifying tournament, said: "I practice with him a lot, he's a great player. I think he's a serious talent, he's going places.
"I knew it was going to be tough but I've been hitting the ball well in practice so it's disappointing to have lost.
"It's not happened many times in my career. I'm bitterly disappointed."
World number six Hendry was the next big name to fall, but had no complaints about the result.
"I started off well, but then I was outplayed," he reflected.
"I had three or four good chances to make it 2-2, but I didn't take them. He (Lee) is certainly a better player than his ranking suggests."
World number two Maguire, who compiled breaks of 55, 96, 58, 40 and 127 to go through, is bidding to become the first professional for three and a half years to make a successful defence of a ranking title.
606: DEBATERonnie O'Sullivan is the last player to have achieved the feat after winning the Welsh Open in 2004 and 2005.
"Although it was 5-1 there were three frames decided on the black ball, so winning them was massive," said Scot Maguire.
"It was looking like 2-2, but I went 3-1 and never really looked back. Now I've got a match under my belt I'll hopefully relax.
"I've not had the heart going like that for a while. You never forget it, but when it comes back it's quite scary, you realise you're under some pressure.
"I'd love to retain my title here this year, I've got so many fond memories of winning here last year."
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