World number four Lewis triumphed 6-2 against the former Lakeside world champion in Sindelfingen to progress to the last 32.
The pair shared the first two legs before Lewis landed a 180 in an 11-dart leg to edge 2-1 up. Bunting levelled in 14 darts and the Stoke ace moved back into the lead at 3-2.
Lewis then pounced on Bunting's misses to break throw and lead 4-2, hit tops again to lead by three legs before finishing 102 to complete the win.
Lewis now plays Ian White in the second round, in a repeat of the 2012 final the pair shared in Sindelfingen which remains the two-time world champion's only previous European Tour win.
Steve West produced the day's best display of finishing with six doubles from seven attempts as he overcame Chris Dobey 6-2 with the aid of checkouts of 130 and 120 to set up a meeting with Michael Smith on Saturday.
Jan Dekker, who averaged 108 as he beat James Wilson, and Mark Webster were among the other winners on day one.
Webster, though, admitted that he is continuing to battle against dartitis, saying: "I'm struggling with my release. At the minute I'm not enjoying my darts but you've got to play through it and I'll give it a go tomorrow."
Friday's results:
Afternoon Session
Ulf Ceder 6-2 Steve Beaton
Krzysztof Ratajski 6-4 Steve Lennon
James Richardson 6-2 Paul Rowley
Matt Clark 6-4 Rene Berndt
Rob Cross 6-3 Luke Woodhouse
Keegan Brown 6-4 Jeffrey de Graaf
Christian Kist 2-6 Jonny Clayton
Gabriel Clemens 3-6 Joe Murnan
Evening Session
Jan Dekker 6-3 James Wilson
Steve West 6-2 Chris Dobey
Dirk van Duijvenbode 6-5 Jermaine Wattimena
Mark Webster 6-4 Bernd Roith
Dimitri Van den Bergh 6-4 Mervyn King
Ron Meulenkamp 5-6 John Henderson
Stephen Bunting 2-6 Adrian Lewis
Max Hopp 6-4 Zoran Lerchbacher
Saturday's order of play:
Afternoon Session (12pm-4pm BST)
Alan Norris v Jan Dekker
Cristo Reyes v Ulf Ceder
Jelle Klaasen v Dirk van Duijvenbode
Simon Whitlock v Rob Cross
Dave Chisnall v Matt Clark
Joe Cullen v Jonny Clayton
Benito van de Pas v Joe Murnan
Kim Huybrechts v Max Hopp
Evening Session (6pm-10pm BST)
James Wade v Mark Webster
Gerwyn Price v Van den Dimitri Van den Bergh
Michael Smith v Steve West
Daryl Gurney v John Henderson
Mensur Suljovic v Krzysztof Ratajski
Peter Wright v James Richardson
Michael van Gerwen v Keegan Brown
Ian White v Adrian Lewis
Click here for full tournament schedule and results
Fast Results
Scores
Racecards 
