A fortuitous goal from Sai van Wermeskerken was enough to hand last season’s Emperor’s Cup winners Kawasaki Frontale a 1-0 win over reigning J-League champions Vissel Kobe in the Super Cup on Saturday. The 48th-minute winner at Tokyo’s National Stadium came off a free-kick into the box, with Hotaru Yamaguchi’s clearance blocked by van Wermeskerken’s leg. The ball traveled toward the goal and Kobe defender Matheus Thuler’s scuffed kick put the ball into his own net. “I’m happy to have made my debut appearance (in Japan) in an important match like this,” said the 29-year-old van Wermeskerken, wh…