Littler, who claimed the title in 2024 before going on to lift the World Championship barely a month later, raced into a 4-0 lead against Czechia’s Sedlacek and eased to a 5-1 victory to open his Group E campaign.
“I really wanted the whitewash win, so I’m a little bit disappointed,” said the teenager. “This is the second major I’ve come to defend. It didn’t go well in the Premier League, but I’m off to a good start here.
“I want to go back-to-back. If I can win tomorrow night, hopefully I can relax on Tuesday. Coming back here brings back great memories, with the sponsor being the same, it all feels like last year’s win again.”
Smith, the 2022 Grand Slam champion, returned after a turbulent year on the circuit to beat Nathan Aspinall 5-3 in a repeat of that final. Aspinall was left frustrated after missing 20 darts at double, allowing Smith to claim the Group A victory.
“To get up there and win that match is emotional, I’m just glad to get over the line,” said Smith, appearing in his first televised event since March’s UK Open.
“Nathan should have won that. I just hung in there and got the job done in the end. I’ve always been a fighter, so to be back on stage and winning matches means the world to me.”
World No. 1 Luke Humphries leads Group A after whitewashing American debutant Alex Spellman 5-0.
Michael van Gerwen survived a major scare in his Group G opener, edging out PDC Women’s Series champion Beau Greaves 5-4. The Dutchman was forced to hold his nerve after Greaves, having fought back from 4-2 down, missed a dart at tops for the match before Van Gerwen sealed victory on double three.
“To win the first game is always a relief,” said Van Gerwen. “I was putting pressure on myself, but this gives me confidence. In my opinion, there’s never been a better women's darts player, but now she needs to push herself. She’s still young, but I have to focus on my own game.”
Van Gerwen now faces Niko Springer, who impressed on debut with a 5-3 win over Gary Anderson.
The biggest shock of the evening came in Group C, where fourth seed Stephen Bunting was beaten 5-4 by the Philippines' Alexis Toylo. Luke Woodhouse tops Group C after defeating Martin Schindler 5-2, while Connor Scutt edged Daryl Gurney 5-4 in Group E.
Earlier, fifth seed James Wade squandered a 3-0 lead to lose 5-4 to Swiss debutant Stefan Bellmont in a Group D upset, missing four darts for the match.
Three-time Grand Slam winner Gerwyn Price also fell at the first hurdle, beaten 5-4 by qualifier Ricky Evans, while Jonny Clayton endured a disappointing start with a 5-1 defeat by debutant Cam Crabtree, who hit all five of his doubles.
Wessel Nijman, who endured a torrid time at last year’s tournament despite averaging over 100 in defeat, finally claimed a deserved Grand Slam win, edging out Josh Rock 5-4 despite the Country Antrim native averaging 109.
Newly crowned European champion Gian van Veen also made a winning start, surviving a spirited performance from Lisa Ashton to prevail 5-4 to the delight of a near 2,000-strong crowd.
Elsewhere, Chris Dobey and Damon Heta both recorded convincing 5-1 wins over Jurjen van der Velde and Martin Lukeman, respectively, while Danny Noppert beat Lukas Wenig 5-4 after the German missed seven match darts.
The 32 players return to the Wolverhampton stage on Sunday for a double session, with losing players from Saturday’s matches meeting to keep their hopes alive, and group winners facing each other.
Results
Danny Noppert 5-4 Lukas Wenig (Group H)
Damon Heta 5-1 Martin Lukeman (B)
Chris Dobey 5-1 Jurjen van der Velde (B)
Ricky Evans 5-4 Gerwyn Price (D)
Stefan Bellmont 5-4 James Wade (D)
Cam Crabtree 5-1 Jonny Clayton (H)
Wessel Nijman 5-4 Josh Rock (F)
Gian van Veen 5-4 Lisa Ashton (F)
Connor Scutt 5-4 Daryl Gurney (E)
Luke Woodhouse 5-2 Martin Schindler (C)
Michael Smith 5-3 Nathan Aspinall (A)
Niko Springer 5-3 Gary Anderson (G)
Luke Humphries 5-0 Alex Spellman (A)
Luke Littler 5-1 Karel Sedlacek (E)
Michael van Gerwen 5-4 Beau Greaves (G)
Alexis Toylo 5-4 Stephen Bunting (C)