Day one of the £450,000 event saw all 32 players in action, with the eight seeded PDC stars pitted against the eight BDO representatives.
A winner of back-to-back Players Championship events last month, Poland’s Ratajski battled back from 3-2 down thanks to some high-pressure finishing to get off to a winning start in Group B.
“To beat such a legend of the game in Raymond is an amazing start for me,” said Ratajski, who will now play Michael Smith in Sunday’s second round of group matches.
“I held my nerve to hit the 72 to go 4-3 up and then, of course, to hit the winning double and now I can take that confidence into my match on Sunday.”
Smith, who missed darts to win the World Series of Darts Finals title last weekend, took 14 attempts to hit the winning double in his 5-4 success over Adam Smith-Neale.
Michael van Gerwen opened his bid for a record-breaking fourth Grand Slam title with a stunning 112.66 average, the third highest ever seen at the tournament, in his 5-1 defeat of Gary Robson.
The world number one fired in six 180s in his opening Group A tie to continue to extend his winning run in Wolverhampton to an incredible 22 matches as he aims to land the £110,000 top prize.
“I think I played really well, my scoring was phenomenal,” said Van Gerwen.
“I always want to put the pressure on myself to perform better because winning is what I’m all about.”
Van Gerwen will now take on Jonny Clayton, who punished ten missed doubles from Joe Murnan to run out a comfortable 5-2 winner in their opener.
Lakeside Champion Glen Durrant enjoyed a comprehensive 5-1 triumph over European Championship runner-up Simon Whitlock in Group F.
A quarter-finalist at last year’s event, Durrant continued his good form in Wolverhampton with a 99 average and he will now meet newly-married Gerwyn Price who wrapped up a 5-2 victory over Andrew Gilding.
“I love every second of playing in this event, the crowd is just amazing,” said Durrant.
“I’m feeling good and I’m playing well so who knows how far I can go this year.”
Last year’s runner-up Peter Wright came through a tense encounter with Jim Williams in Group E, with the Scot missing five match darts to allow the Welsh debutant to take the tie to a nervy deciding leg.
With Williams poised on 95 to win the tie, Wright fired in a perfectly-timed 171 before pinning double four to claim the two points, and he will face Max Hopp next.
The opening game of the tournament saw German number one Hopp come back from 2-0 to win five of the last six legs against Josh Payne 5-3, including a 123 finish on the bullseye, for a 5-3 win.
In Group D, Ian White produced an impressive 104.6 average in his 5-1 win over Steve Hine, while World Matchplay and UK Open champion Gary Anderson opened his bid for a first Grand Slam crown with a 5-2 win over German Michael Unterbuchner.
Austria’s Mensur Suljovic got off to a winning start in Group G with a solid display to beat former Lakeside Champion Scott Mitchell 5-2, and Stephen Bunting landed a 170 checkout in his 5-3 win over young German Martin Schindler.
World Champion Rob Cross took his chances to secure a 5-2 win over Mark McGeeney as the Lakeside Championship runner-up missed 20 darts at a double in Group H, and World Youth Champion Dimitri Van den Bergh produced an assured display to beat Ryan Searle 5-3.
In Group C, European Champion James Wade began his charge for a third successive TV title with a 5-0 whitewash of Dutchman Wesley Harms and he will now take on Keegan Brown, whose 153 finish proved to be the turning point in his tight 5-4 win over Mark Webster.
Saturday’s winners will face each other on Sunday, with Saturday’s losers facing each other. The final group matches will take place on Monday and Tuesday, with the top two players from each group progressing to the last-16 knockout stage.
The tournament will be broadcast live on Sky Sports and through the PDC’s worldwide broadcast partners, as well as through PDCTV-HD for Rest of the World Subscribers.
2018 bwin Grand Slam of Darts
Schedule of Play
Saturday, November 10
Groups E-H First Matches
Max Hopp 5-3 Josh Payne (E)
Gerwyn Price 5-2 Andrew Gilding (F)
Dimitri Van den Bergh 5-3 Ryan Searle (H)
Stephen Bunting 5-3 Martin Schindler (G)
Glen Durrant 5-1 Simon Whitlock (F)
Mensur Suljovic 5-2 Scott Mitchell (G)
Rob Cross 5-2 Mark McGeeney (H)
Peter Wright 5-4 Jim Williams (E)
Groups A-D First Matches
Keegan Brown 5-4 Mark Webster (C)
Jonny Clayton 5-2 Joe Murnan (A)
Ian White 5-1 Steve Hine (D)
Michael Smith 5-3 Adam Smith-Neale (B)
James Wade 5-0 Wesley Harms (C)
Krzysztof Ratajski 5-3 Raymond van Barneveld (B)
Gary Anderson 5-2 Michael Unterbuchner (D)
Michael van Gerwen 5-1 Gary Robson (A)
Sunday, November 11
Afternoon Session (1300 GMT 11pm AEDT)
Groups E-H Second Matches
Ryan Searle v Mark McGeeney (H)
Josh Payne v Jim Williams (E)
Martin Schindler v Scott Mitchell (G)
Simon Whitlock v Andrew Gilding (F)
Mensur Suljovic v Stephen Bunting (G)
Rob Cross v Dimitri Van den Bergh (H)
Gerwyn Price v Glen Durrant (F)
Peter Wright v Max Hopp (E)
Evening Session (1900 GMT 4am AEDT)
Groups A-D Second Matches
Steve Hine v Michael Unterbuchner (D)
Joe Murnan v Gary Robson (A)
Mark Webster v Wesley Harms (C)
Raymond van Barneveld v Adam Smith-Neale (B)
James Wade v Keegan Brown (C)
Michael Smith v Krzysztof Ratajski (B)
Michael van Gerwen v Jonny Clayton (A)
Gary Anderson v Ian White (D)
Best of nine legs
2018 bwin Grand Slam of Darts Tables
|Michael van Gerwen||1||1||0||+4||2|
|Raymond van Barneveld||1||0||1||-2||0|
|Dimitri Van den Bergh||1||1||0||+2||2|