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 on Wednesday.
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.
Bingham, however, clinched victory with a superb break of 125.
Murphy had to withstand a fightback from Trump as he reached the semi-finals for the first time since 2015.
Trump resumed 10-6 behind 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.
Earlier Selby, already 6-2 ahead, won four consecutive frames with the aid of breaks of 96, 58 and 66 before Welshman Williams stopped the rot with a 79.
However, two more half-centuries helped Selby claim the three frames he needed to complete a 13-3 victory.
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 told the PA news agency: "We'll find out if that's a good omen over the next few days.
"But I feel as though I'm playing as good as back then, if not better at the moment."
Wilson, meanwhile, was pleased by the way he had yet again defeated a highly-fancied contender for the title.
"Last year Judd was tipped to win the event and I managed to beat him, this time Neil was tipped for it and I have knocked him out," said the 29-year-old.
"I believe in what I can do, I can beat anyone on my day. I don't see the point in being in this sport to just turn up for the money and say quarter-finals will do.
"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."
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.