Unranked Sandblom, a Hawaii Pacific University freshman attending school on a tennis scholarship, upset second-seeded David Lam of Oahu for the men's singles title.
Third-ranked Ptaszek, who plans to enter BYU-Hawaii in January, defeated sixth seeded Keawe Ayau, a Kamehameha Schools senior, for the women's singles crown.
And if that wasn't aloha enough, Ptaszek later teamed with Swedish pal Anneli Ornstedt, a BYU-Hawaii senior, to win the women's doubles title.
''We try hard to please our visiting players,'' said tournament director Bernard Gusman.
While Ptaszek dispatched Ayau, 6-2, 6-0, in 50 minutes, Sandblom battled Lam for two hours before winning, 6-3, 6-7 (5-7), 6-2.
Oahu's only Grand Prix-designated tourney was scheduled to pay out $5,000 in prize money but because of amateur rules governing students receiving cash, far less money was distributed.
''I understand that all the students could have used the money but rules are rules,'' Gusman said.
As students, Ptaszek, Ayau, Ornstedt and men's winner Sandblom were not allowed to accept cash for play.
''There goes my Hawaiian shopping spree,'' said Ptaszek, when told that the $400 for winning the women's singles, and the $200 as her share for winning doubles would be withheld. Men's singles winner Sandblom would have received $800 for his efforts.
Sandblom and Lam played the first two sets of the men's final almost even - each mixing booming serves, well-placed ground strokes and accurate volleys.
While the first set had only a single service break - by winner Sandblom in the eighth game - the second set had four breaks, two by each player.
''David (Lam) gained his composure in the second set, placing Sandblom on the defensive,'' Gusman said. ''His drop shots and volleys were all falling in.''
The Swede had his share of service problems. He lost six second- set points in a row, several by double-faulting.
''I can't understand it,'' Sandblom said, ''I'm seldom called for foot-faulting in tournaments. And here I've been penalized several times. I broke strings on two rackets. This left me with a racket that was unfamiliar."
The pace slowed in the third set, each player feeling the effects of the heat and rigors of earlier sets. And when Sandblom broke Lam's serve in the sixth game and held his serve in the seventh, victory was his.
''A big win,'' the Swede said.
In the women's final, the 5-foot-9 Ptaszek roared to a 3-0 first-set lead before Ayau could load her guns. ''A terrible start. I've played better,'' Ayau said.
''No local woman serves or hits harder,'' said spectator Kim Jenkins.
Added Ayau: ''She was too strong.''
Ptaszek took just 20 minutes in winning the second set.
''In Denmark we play indoors,'' Ptaszek said. ''Fortunately,I wasn't bothered by the heat or sun.''
Both singles winners beat the top seeds during earlier rounds. Ptaszek topped Ornstedt, 6-3, 6-2, in the semifinals, while Sandblom beat Johan Carlsson, 7-6, 7-5, in the round of 16.
In the men's doubles finals, David Lam teamed with Howard Tacub to beat brothers Alika and Kekua Beamer, 7-6 (8-4), 6-4.
The women's doubles title was won by Ptaszek and Ornstedt, who defeated Kanani Galolo and Kim Uyema 6-3, 6-2.