Jose De Sousa became the first Portuguese player to reach a televised quarter-final by defeating Dave Chisnall in the BoyleSports Grand Slam of Darts on Friday, as Simon Whitlock, James Wade and Dimitri Van den Bergh also progressed.
De Sousa has made huge strides in less than two years on the PDC circuit full-time, and will continue his progression in Coventry after booking a spot in Sunday's last eight with a 10-7 win over Chisnall.
A see-saw game saw Chisnall take the opening two legs before De Sousa claimed eight in a row to move within touching distance of a historic victory.
Chisnall regained his range on the doubles to take five legs in reply as he cut the gap to one leg, but he crucially missed one dart at double 18 to level in leg 18.
De Sousa hit the same bed to lead 9-7, before pinning double 12 to ensure his spot in the last eight for the first time on television.
"This is a dream for me," said De Sousa. "I'm in the Grand Slam for the first time and in the quarter-finals, so it's amazing.
"It was a strange game, but I'm happy that I won. I started much better than Chizzy and I punished him, then I missed a little bit and he punished me, and at the end I came strong again."
De Sousa also landed a nine-darter in the European Championship last month and won a European Tour event in October, and has broken into the world's top 32.
"It's the best year of my life in darts," he added. "For me it is not a surprise, but for many people maybe it is. My confidence is getting better and better and I'm starting to play like the top players."
Dimitri Van den Bergh's bid to win a second televised title of 2020 continued with another impressive display as he raced past Jonny Clayton 10-3 with a 103 average and eight 180s.
The World Matchplay champion landed three 12-darters and a 13-dart leg in a high-quality opening as he created a 5-2 cushion to move halfway towards the quarter-finals.
Clayton hit back in leg eight, but back-to-back 14-darters for Van den Bergh were followed by a 13-dart leg as he moved 9-3 up, before sealing his place in the last eight with a 110 checkout.
"So far it's going very well and I'm really proud," said Van den Bergh, who now plays Gerwyn Price or Nathan Aspinall.
"I feel like I played a terrific game from the start until after the second break - I kept Jonny under pressure and I was phenomenal in parts.
"I felt that here and there I could be a little more focused, but I'm really happy to be in another quarter-final. I'm on a winning streak and I want to keep this going.
"I'm buzzing. I'm really happy - inside I'm having explosions of happiness. I'm dreaming about winning this and I hope I can make my dreams come true again."
Two-time finalist James Wade booked his place in the last eight, to face either Devon Petersen or Damon Heta, by defeating Ian White 10-4 in their tie.
White held his own during the early exchanges, landing two 13-darters as he shared the first six legs, but three misses in leg eight allowed Wade to pull two legs clear for the first time at 5-3.
White replied by finishing 85 on the bull, but Wade pulled clear with a 96 finish and an 11-darter in a run of five straight legs to ensure a first Grand Slam quarter-final since 2016.
"I'm really happy," said Wade. "I'm happy to move forwards and I still know I can win tournaments.
"Ian missed quite a few trebles at the wrong times and doubles at the wrong times and gave me way too many opportunities, but I'll take them if they're there."
Simon Whitlock reached the quarter-finals for a fourth time with a 10-6 defeat of Adam Hunt to bring the qualifier's run in Coventry to an end.
The Australian's strong form in televised events continued as he led throughout against Hunt, who hit back from 2-0 down to 3-2 but paid for four missed doubles to level the tie in leg six.
Hunt did take out 112 to pull back to 4-3, and after Whitlock finished 116 the youngster checked out 70 to move back to within a leg again, but Whitlock pulled clear to close out the win five of the next seven for victory.
"It was a tough match but I made it tough for myself, I didn't show the form I have recently," said Whitlock. "I didn't feel good and I was really nervous, but I've got through it.
"I tried as hard as I could but Adam kept coming back at me. I battled away and got the win, but I'll have to play better in the next match."
Whitlock will now play either Michael van Gerwen or Gary Anderson, and he added: "If I play like I have done, I can beat either of them. I have to perform and I'll be better than I was tonight."
The second round concludes on Saturday with the remaining four matches, headlined by the clash between former World Champions Michael van Gerwen and Gary Anderson.
Reigning Grand Slam champion Gerwyn Price takes on world number six Nathan Aspinall in another tasty contest, while England World Cup team-mates Michael Smith and Rob Cross face off and South Africa's Devon Petersen meets Australia's Damon Heta.
The tournament is being broadcast live on Sky Sports, as well as through the PDC's international broadcast partners including RTL7 and DAZN and for PDCTV Rest of the World Subscribers.
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BoyleSports Grand Slam of Darts
Friday November 20
Dimitri Van den Bergh 10-3 Jonny Clayton
James Wade 10-4 Ian White
Simon Whitlock 10-6 Adam Hunt
Jose De Sousa 10-7 Dave Chisnall
Saturday November 21 (1900 GMT)
Michael Smith v Rob Cross
Devon Petersen v Damon Heta
Michael van Gerwen v Gary Anderson
Gerwyn Price v Nathan Aspinall
Best of 19 legs
Quarter-Finals Draw Bracket
Van Gerwen/Anderson v Simon Whitlock
Smith/Cross v Jose De Sousa
Petersen/Heta v James Wade
Price/Aspinall v Dimitri Van den Bergh