Stuart Bingham and Shaun Murphy both came through hard-fought quarter-finals on Wednesday to ensure three of the last four players left vying for this year's world snooker crown are former champions.
Bingham, the 2015 world champion, edged out Anthony McGill 13-12.
Meanwhile, 2005 title-winner Murphy defeated current world number one Judd Trump, who took the title two years ago, 13-11.
Those matches were in marked contrast to the two quarter-finals completed earlier at Sheffield's Crucible Theatre.
Mark Selby overwhelmed fellow three-time former champion Mark Williams 13-3 while 2020 finalist Kyren Wilson reeled off five frames in a row to seal a 13-8 victory over 2010 champion Neil Robertson.
Wilson will now play Murphy in the semi-finals, with Selby facing Bingham in an all-English last four.
Bingham won a final-frame decider to see off Scotland's Anthony McGill 13-12.
McGill, who had caused the shock of the tournament by knocking out reigning champion Ronnie O'Sullivan in the previous round, made a fine break of 106 to extend his overnight lead to 10-7.
But Bingham, who came through qualifying, won five consecutive frames only for McGill to take the next two to level at 12-12.
- 'Holy Grail' -
Bingham, however, clinched victory with a superb break of 125.
"It's just the Holy Grail of the sport and I'm proud of the way I held it together because it's not easy playing under that kind of pressure," Bingham told Britain's Press Association news agency.
Trump resumed 10-6 behind against Murphy but won five of the evening session's first six frames and levelled the match with a break of 111.
Murphy, however, regained his composure, breaks of 70 and 62 securing a semi-final with Wilson.
"Maybe this week turns my bad season around a little bit. I don't think one good run can delete 20 bad ones, but I'm two wins away from capping off a very bad year in a very good way," said Murphy.
Trump, left to rue what might have been, said: "At 11-11 if I didn't miss that black I was in full control, and I let him back in easy. It was mine to lose and it is disappointing I didn't make it harder for him."
Earlier Selby, already 6-2 ahead, won four consecutive frames before Welshman Williams briefly stopped the rot.
The last quarter-final to end with a session to spare was Selby's 13-3 win over Marco Fu in 2017 on his way to the title and the 37-year-old said: "We'll find out if that's a good omen over the next few days."
Australia's Robertson, the last player from outside Britain left in the tournament, came to Sheffield with high hopes of lifting the trophy after victories in the Tour Championship and the UK Championship.
But he was well-beaten by Wilson, who said: "I believe in what I can do, I can beat anyone on my day.
"If I lose in the semi-finals I will go away from here annoyed, it wouldn't be good enough. I want to push on and I believe I can win it."