It was almost a lights-to-flag win for the Hyundai i20 N Rally2 driver, who snatched the lead on the first gravel test of the event.
Suninen built up the majority of his winning margin during Friday’s opening leg - winning seven out of nine classic speed tests around Lankamaa and Laukaa.
A brief scare on Saturday morning when the car briefly lost power almost allowed Škoda Fabia Rally2 rival Emil Lindholm into contention, but the pair remained very evenly matched for the remainder of the weekend.
Suninen ended 7.7sec to the good as well as placing eighth in the overall rally standings. It was a much-needed result for the 28-year-old - especially as he previously retired from the lead in both Portugal and Italy.
"It was a really good rally for us and we are feeling great,” he beamed. “I think we have done a very good job of developing the car and now it's on the winning pace, so that's the most important thing."
Volkswagen Polo GTI driver Egon Kaur was a distant third. He trailed Lindholm by two minutes but had just 10.6sec in hand over Hayden Paddon’s Hyundai New Zealand machine.
Teemu Asunmaa brought his Škoda home more than two minutes further back to complete the top five, while Eerik Pietarinen ended sixth overall in another Polo.
Lindholm took WRC2 Junior honours and moved into the lead of the series open to drivers aged under 30, while Freddy Loix - also driving a Škoda - emerged as victor WRC2 Masters Cup.