Reigning Betfred World Matchplay champion Rob Cross was amongst the first round casualties in Milton Keynes whilst four other World Champions were safely through to the second stage.
Mensur Suljovic, meanwhile, came out on top against Jamie Hughes in what was arguably the tie of the round.
2019 winner Cross found himself on the wrong end of a giant killing by Gabriel Clemens, becoming the first title-defender in 14 years to bow out in the first round.
The German punished Cross' poor finishing with an impressive doubles conversation rate of 55% to claim a famous 10-8 victory on his Matchplay debut at the Marshall Arena.
Although Cross responded to early breaks of throw to move 6-5 ahead, Clemens kept his composure to regain the lead and dump the Englishman out of the competition on a double eight.
The opening stage provided no other shocks, as four past and present world champions were safely through to round two.
Top seed Michael van Gerwen edged Brendan Dolan in a 10-7 victory, whilst reigning world champion Peter Wright survived a scare against Jose De Sousa and Gary Anderson dismissed Justin Pipe with little discomfort.
The pick of the action saw Mensur Suljovic come from behind to claim a dramatic win over Jamie Hughes, with Joe Cullen beating Ian White in the competition's first sudden death decider.
Suljovic looked to be heading home early when Tipton-born Hughes checked out 118 to move 9-7 ahead, but three straight legs helped the Austrian snatch a 12-10 victory from the brink of elimination.
Cullen - ranked 18th on the PDC circuit - was thrashed by opponent White in last year's tournament, failing embarrassingly to pick up a single leg in a 10-0 rout.
This year, however, the clash was totally opposite in nature as the game went down to the wire, Cullen fighting back from 8-4 down to win five successive legs in clinical style before a stagnated finale saw The Rockstar grab the deciding double at a sixth attempt.
Elsewhere, two-time world champion Adrian Lewis booked his place in the second round with a close 11-9 win over Steve Beaton.
Rotten runs and poor performances
The World Matchplay opening round continued to hold a curse over Welshman Gerwyn Price, who lost out to rising star Danny Noppert.
Twenty-nine-year-old Noppert struck five 180s as the Ice Man struggled to move into second gear, falling to his fourth successive first round exit in the competition.
Although the remaining competition favourites were safely through, the majority have had better days at the oche and were quick to admit so in their post-match pressers.
"A win is a win and it doesn't matter how you win, but I made it hard work for myself and I struggled today," van Gerwen told the PDC.
"I'm relieved to get over the line but I'm really disappointed with the way I played," said Peter Wright after his win over Jose De Sousa.
'I pretended I was at Blackpool'
Players are, understandably, still adjusting to the new norms in sport.
Although darts professionals are used to the occasional behind-closed-doors competition, big-stage events like the World Matchplay never fail to attract fans in their thousands, and players often look to their spectators for an extra kick when the stakes are high.
The lack of vocal support - or even the occasional banter - has been sorely missed.
An absence of crowd noise therefore proved to have some kind of effect on performances - but Simon Whitlock had his own inventive solution.
"It was strange at first but I pretended I was at Blackpool and that I had the crowd there, and that's what kept me going," he told the PDC after beating Ryan Joyce 10-4 on day one.
Round two: the key battles
Several notable ties await in the second round, with Whitlock taking on Michael van Gerwen and Michael Smith matched with Mensur Suljovic.
Gabriel Clemens, who dumped Rob Cross out of the tournament, faces Polish former World Masters winner Krzysztof Ratajski in a key battle between two potential dark horses.
The legs target moves up to 11 for the second round, with competitors now battling to the best of 21.
One final first round fixture remains, however, as Dimitri Van den Bergh and Nathan Aspinall fight for the final spot in the last 16.
The story so far
(R1 - 18/07) Simon Whitlock 10-4 Ryan Joyce
(R1 - 18/07) Krzysztof Ratajski 10-4 Jermaine Wattimena
(R1 - 18/07) James Wade 12-10 Keegan Brown
(R1 - 18/07) Michael van Gerwen 10-7 Brendan Dolan
(R1 - 18/07) Gary Anderson 10-5 Justin Pipe
(R1 - 19/07) Mensur Suljovic 12-10 Jamie Hughes
(R1 - 19/07) Glen Durrant 10-3 Jeffrey de Zwaan
(R1 - 19/07) Gabriel Clemens 10-8 Rob Cross
(R1 - 19/07) Peter Wright 10-8 Jose De Sousa
(R1 - 19/07) Michael Smith 10-3 Jonny Clayton
(R1 - 20/07) Vincent van der Voort 10-6 Dave Chisnall
(R1 - 20/07) Joe Cullen 13-12 Ian White
(R1 - 20/07) Daryl Gurney 10-5 Ricky Evans
(R1 - 20/07) Danny Noppert 10-7 Gerwyn Price
(R1 - 20/07) Adrian Lewis 11-9 Steve Beaton
(R1 - 21/07) Nathan Aspinall v Dimitri Van den Bergh
(R2 - 21/07) Michael Smith v Mensur Suljovic
(R2 - 21/07) Gary Anderson v James Wade
(R2 - 21/07) Michael van Gerwen v Simon Whitlock
(R2 - 21/07) Gabriel Clemens v Krzysztof Ratajski
(R2 - 22/07) Daryl Gurney v Vincent Van de Voort
(R2 - 22/07) Peter Wright v Glen Durrant
(R2 - 22/07) Danny Noppert v Adrian Lewis
(R2 - 22/07) Joe Cullen v Nathan Aspinall/Dimitri Van den Bergh