Ronnie O'Sullivan recovered from a slow start to beat Ding Junhui 5-2 in the Northern Ireland Open quarter-finals as Judd Trump also reached the last four.
Breaks of 121 and 87 put the Chinese star 2-0 ahead but breaks of 58, 59, 70 and 79 helped world champion O'Sullivan set up a semi-final with Ali Carter.
"I dragged him [Ding] down to my level. I had to dig in deep," O'Sullivan, 44, told Eurosport in Milton Keynes.
Trump produced a top break of 112 as he beat Scotland's Scott Donaldson 5-1.
The 2019 world champion shared the opening two frames with Perth-born Donaldson but a break of 70 in the third restored Trump's advantage and his century in the next was followed by further runs of 52 and 86 as he clinched victory.
Trump's semi-final opponent will be compatriot and world number 67 David Grace who defeated China's Bingtao Yan 5-2 to complete an all-English semi-final line-up.
O'Sullivan, who hit the headlines on Thursday after loudly breaking wind midway through his match against Matthew Stevens, said that he was "embarrassed at times" with his form against Ding, who will begin the defence of his UK Championship title next week.
"My positioning was amateurish compared to his," said the six-time world champion.
Carter reached the semi-finals by beating Norway's Kurt Maflin 5-3.
World Snooker has been running all of its tournaments in Milton Keynes because of the Covid-19 pandemic.
The Marshall Arena has on-site accommodation, meaning everyone involved in the tournament can be contained at the complex.
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