The win, fashioned out off Bulabog Island with winds blowing a steady 17 knots, quickly established Radis as the formidable favorite in the five-round event although Ruamsap, third on the Asian Tour, and Guams Conrad Kerber remained close.
Filipinos Visegrip Fajermo, Manny Cabili and Bingo Moreno finished fourth-sixth among 66 competitors from 13 countries.
The second round was being completed yesterday afternoon.
Simultaneous with the downwind slalom is the speed trials held in the southern end of Bulabog Beach where participants pass one a time through a gate and are clocked with an electronic speed gun.
Radis had the fastest time of 50 kph while Philstar.com featured athlete Filipina Nenette Graf and Korean Yun Hee Lee tied with a speed of 38.6 kph.
Racing continues until Saturday. Also featured are an endurance event the Winduro and a Fosters Forward Loop event on the waves that break on the reef.
The tour is presented by Fosters with official magazine Action Asia and on-line partner Philstar.com. The Boracay International Funboard Cup is supported by Asian Spirit, Neil Pryde, Maui & Sons, Philippine Airlines, Department of Tourism and Green Yard Funboard Center. Each event on the Adecco AWT is filmed for international broadcast to over 170 million viewers in over 100 countries worldwide.
For more information on the event, visit the Cup web site at www.windsurfingPhilippines.com/bfcl