Michael van Gerwen overcame a scare against Damon Heta before booking his second round spot at the Betfred World Matchplay with a 10-7 victory in Blackpool on Monday.
Van Gerwen scooped the World Matchplay titles in 2015 and 2016, but had to come from 6-4 down to keep alive his challenge to claim the Phil Taylor Trophy for a third time.
The Dutchman posted a 13-darter as he took a 3-1 lead, and he also moved 4-2 up before Heta claimed four successive legs to move himself two clear.
Van Gerwen stormed back with successive 84 finishes to tie the contest and then punished Heta's misses to move 8-6 up before a 97 checkout gave him a fifth straight leg.
Heta took the 16th leg to keep his hopes alive, but Van Gerwen opened the next with two 180s to give himself the breathing room to miss match darts in two visits before wrapping up the win.
"I had to work hard today but I got the job done," said Van Gerwen. "It was hard work and there's more in the tank but I've got the first round out of the way.
"Damon had some good finishing that hurt me and when you put so much pressure on your shoulders you have to escape somehow and I did that.
"I never give up and I know when I give 100 percent I'll always put myself in a position where I can hurt someone.
"I didn't play my absolute A-game, but hopefully that can come later in the tournament. I feel it's coming, but I just have to keep winning games."
Van Gerwen now plays Ian White, who won through to the last 16 for the eighth time at the World Matchplay as he out-lasted Daryl Gurney with a 10-7 success.
The first game back in front of a near-capacity crowd saw White and Gurney produce a thriller which featured five ton-plus checkouts.
Gurney's early finishes of 101 and 130 were cancelled out by checkouts of 84 and 117 by White as the Stoke ace took a 4-2 lead before extending that advantage to 8-3.
Gurney took out 116, 80, 76 and 121 on the bull to keep his hopes alive at 9-7, but the 2019 semi-finalist missed three doubles to continue the fightback and White regained his range on the outer ring to land double six for victory.
"I loved having the crowd back tonight and it was special," said White. "I enjoy Blackpool and love this arena, and I think the crowd really enjoyed the game too.
"It was a hard game between the pair of us but we are so evenly matched in the rankings. I always seem to miss a few doubles and make it harder for myself but tonight was my night.
"It's nice to have gone my way tonight with Daryl missing a few doubles. I let Daryl in quite a lot and I need to stop doing that."
Nathan Aspinall tasted victory in the World Matchplay for the first time with a battling 10-6 win over Mervyn King, ending the former semi-finalist's Blackpool hopes.
Aspinall has lost in the first round for the past two years, including against King at the Winter Gardens in 2019, but delighted the supportive crowd to move into the last 16.
The former UK Open champion raced into a 4-0 lead, only to miss his chance to win a fifth leg as King stepped in to cut the gap to one leg.
Crucially, Aspinall denied King the chance to level on three occasions, capitalising on missed doubles from the Norfolk ace, before a key double 18 gave him breathing space at 9-6 and a 72 finish wrapped up the win.
"It's my first win in the World Matchplay so I'm very happy, and to win in front of a crowd again was amazing," said the 30-year-old.
"I played here two years ago and the crowd delivered again - it's a great atmosphere and I had a fantastic night.
"I didn't play my best darts but I don't care because I won. I went into the first break feeling positive at 4-1 but the middle part was a good battle between us.
"I can look forward to the second round on Wednesday now, but I'll have to play better than that."
Aspinall now meets Gary Anderson in round two, with the 2018 champion overcoming Stephen Bunting 10-5 in the final tie of the night.
The Scot opened up an early 2-0 lead and retained his advantage throughout, denying Bunting the chance to level in leg six before three successive 14-darters moved him 7-3 up.
Bunting took two of the next three, but Anderson swiftly ended his fightback and took out 70 to begin his challenge to reach a third final in four years in comfortable fashion.
"It was a bit scrappy but I'll take it," said Anderson. "Stephen didn't score as well as he can and I was playing with new darts - they were going fine in practice but it wasn't quite the same on stage.
"I can't quite work it out so I'll look at it for the next game, because Nathan is playing well and he's a cracking player.
"It's good to see the crowds back. The PDC have done great to get us playing darts behind closed doors, but it's nice to have the fans in again. We've got used to the quietness and I think you'll see some players struggle!"
The second round begins on Tuesday with the opening four ties, including the all-Welsh contest between World Champion Gerwyn Price and Premier League winner Jonny Clayton.
Reigning champion Dimitri Van den Bergh faces Dave Chisnall, giant-killer Luke Humphries will play Poland's Krzysztof Ratajski and 2019 winner Rob Cross plays Callan Rydz.
The action will be broadcast live on Sky Sports in the UK, through the PDC's worldwide broadcast partners including DAZN and RTL7, and on PDCTV for Rest of the World Subscribers.
2021 Betfred World Matchplay
Monday July 19
4x First Round
Ian White 10-7 Daryl Gurney
Nathan Aspinall 10-6 Mervyn King
Michael van Gerwen 10-7 Damon Heta
Gary Anderson 10-5 Stephen Bunting
Tuesday July 20 (1900 BST)
4x Second Round
Rob Cross v Callan Rydz
Luke Humphries v Krzysztof Ratajski
Gerwyn Price v Jonny Clayton
Dimitri Van den Bergh v Dave Chisnall
Wednesday July 21 (1900 BST)
4x Second Round
Michael Smith v Jose de Sousa
Gary Anderson v Nathan Aspinall
Michael van Gerwen v Ian White
Peter Wright v Joe Cullen
Second Round: best of 21 legs.
Each game must be won by two clear legs, with up to a maximum of five additional legs being played before the sixth additional leg is sudden-death. For example, should a Second Round game (best of 21 legs) reach 13-13, then the 27th leg would be the final and deciding leg.