Richard Veenstra, Kenny Neyens and Danny van Trijp each secured qualification for one of the year's first three European Tour events.
Former Lakeside semi-finalist Veenstra will make his European Tour debut at the Hungarian Darts Trophy from September 3-5 after winning the day's first qualifier.
The experienced Dutchman defeated Lukas Wenig 5-3 in the final to book his place at the Papp László Sportaréna in Budapest.
A further two European Associate Member Qualifiers followed at the H+ Hotel, featuring players who do not hold a 2021 PDC Tour Card.
Belgian youngster Kenny Neyens, who won a Challenge Tour event a day earlier, will make his first European Tour appearance since 2017 at the Gibraltar Darts Trophy (ET2) from September 24-26.
Neyens claimed a 5-2 victory over Gillian Koehoorn in the ET2 decider.
The final qualifier of the day saw 24-year-old Dutchman Danny van Trijp defeat France's Thibault Tricole 5-2 to book his place in ET3. Further details of this event will be confirmed in due course.
View all results in the Match Centre.
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ET1-3 European Associate Member Qualifiers Results
H+ Hotel, Niedernhausen
Monday July 5
ET1 European Associate Member Qualifier
Semi-Finals
Lukas Wenig 5-1 Patrick Bulen
Richard Veenstra 5-2 Rusty-Jake Rodriguez
Final
Richard Veenstra 5-3 Lukas Wenig
ET2 European Associate Member Qualifier
Semi-Finals
Kenny Neyens 5-3 Richard Veenstra
Gillian Koehoorn 5-3 Rowby-John Rodriguez
Final
Kenny Neyens 5-2 Gillian Koehoorn
ET3 European Associate Member Qualifier
Semi-Finals
Thibault Tricole 5-4 Damian Mol
Danny van Trijp 5-4 Kevin Blomme
Final
Danny van Trijp 5-2 Thibault Tricole