England and Wales survived scares, while reigning champions Scotland were forced to come through a doubles decider to reach the quarter-finals of the World Cup of Darts in Frankfurt.
Top seeds Michael Smith and James Wade, who are aiming to win England's first World Cup crown since 2016, battled past Latvia's Madars Razma and Hauris Gleglu in a hard-fought contest. Smith blitzed Gleglu in four legs, while Wade was edged out 4-3 by Latvian captain Madars Razma.
The English duo produced a professional performance in the doubles to progress, running out 4-2 winners with a 96 average.
Wales' Gerwyn Price and Jonny Clayton survived a major scare before edging out Austria's Mensur Suljovic and Rowby-John Rodriguez in a dramatic deciding-leg shoot-out.
John Henderson whitewashed Jerónimo to set Scotland on their way against Portugal, but former Grand Slam champion Joe De Sousa battled past World Champion Wright 4-3 in a high-quality affair to prolong the drama.
However, De Sousa was left to rue an astonishing miscount in the opening leg of the Pairs match, hitting a maximum to burst their score of 181, and the Portuguese duo never recovered as Wright and Henderson capitalised to clinch a whitewash win.
For the first time in World Cup history, the quarter-final line-up features all eight seeded nations, with Scotland taking on England in the last eight.
"I'm proud to wear the shirt and England are through to the next round, so that's all that matters," reflected Smith, who landed two maximums in the Pairs contest.
"Michael is the best player in the world at the moment, but I know I can match him, so it hurts when you don't perform," Wade added.
"I am gutted with how I played. I tried so hard, but I promise I will be better tomorrow."
Dutch duo Danny Noppert and Dirk van Duijvenbode sent out a statement to their title rivals with an imperious display in their second round win over 2019 finalists Republic of Ireland.
The pair fired in nine 180s across their respective matches, with UK Open champion Noppert landing five in the final three legs of his 4-1 win over William O'Connor.
However, it was Van Duijvenbode who stole the headlines, posting a stunning 110.64 average to dismantle Steve Lennon in quick-fire fashion, sealing the deal in 11 and 12 darts.
Australia's Simon Whitlock and Damon Heta battled past spirited Swedes Johan Engstrom and Daniel Larsson to reach their third consecutive World Cup quarter-final.
Whitlock defied a mid-game slump to claim a deciding-leg victory over Engstrom, while a sensational 132 finish from Larsson inspired him to a surprise 4-3 win against Heta.
However, the experience of the fifth seeds paid dividends in the Doubles decider, as they maintained their title tilt with a 4-1 triumph.
The 2012 runners-up now play Belgium for a semi-final spot, after Dimitri Van den Bergh and Kim Huybrechts steered the fourth seeds to a convincing 2-0 victory over Poland.
Van den Bergh opened the Belgian account with a routine 4-1 win over a below-par Krzysztof Ratajski, before Huybrechts maintained his impressive Singles record with a 4-2 win over 18-year-old debutant Sebastian Bialecki.
Host nation Germany will play Wales in Sunday afternoon's quarter-finals, after seventh seeds Gabriel Clemens and Martin Schindler relinquished just two legs in their last 16 tie against Denmark.
Schindler eased past Vladimir Andersen 4-1 in the opening rubber, before Clemens saw off Andreas Toft Jorgensen by the same scoreline, averaging 93 and crashing in two 180s to complete the job.
Elsewhere, Northern Ireland will play Netherlands in the last eight, after Daryl Gurney and Brendan Dolan sealed a spot in their second consecutive World Cup quarter-final with a convincing win over New Zealand.
Gurney defeated New Zealand debutant Ben Robb in the afternoon's curtain-raiser, taking out a 117 finish en route to a 4-2 victory.
Dolan then reeled off four straight legs to defeat Warren Parry by the same scoreline, averaging almost 99 and closing out proceedings with legs of 14, 12 and 13 darts.
The £350,000 tournament concludes on Sunday, with the afternoon session's quarter-finals followed by the semi-finals and final in the evening session at the Eissporthalle.
2022 Cazoo World Cup of Darts - Saturday June 18 results
Northern Ireland 2-0 New Zealand
Netherlands 2-0 Republic of Ireland
Wales 2-1 Austria
Germany 2-0 Denmark
Australia 2-1 Sweden
Belgium 2-0 Poland
England 2-1 Latvia
Scotland 2-1 Portugal
Schedule for Sunday June 19
Netherlands vs Northern Ireland
Wales vs Germany
Belgium vs Australia
England vs Scotland
Wales/Germany vs Netherlands/Northern Ireland
England/Scotland vs Belgium/Australia
England/Scotland/Belgium/Australia v Wales/Germany/Netherlands/Northern Ireland