Undefeated southpaw fighter Rex Tso Sing-yu will fight Japan's Atsushi Kakutani in his next bout on May 31 as he targets a world title in November, his handlers announced. The 26-year-old Hong Kong star will fight his second Japanese opponent after defeating Mako Matsuyama in an eighth-round knockout in Ring of Gold in February and the "Wonder Kid" can expect another tough fight on the undercard of Featherweight Fury at the CotaiArena. Tso will be looking to extend his winning streak to 13-0 against Kakutani, who last year fought and lost for the World Boxing Council (WBC) light-flyweight title against Mexico's Adrian Hernandez. Tso's fight will be over 10 rounds and it will be the first defence of his World Boxing Organisation (WBO) Asia Pacific junior bantamweight title he won in February. Kakutani (14-4-1, 7 KOs), 29 next week, turned professional in 2008. Tso (12-0-0, 8 KOs) is already in the Philippines training for the 10-round fight and his trainer and coach Jay Lau Chi-yuen said Kakutani would present tough opposition for his protégé. "Kakutani actually knocked Hernandez down in the first round of their world title fight last year before Kakutani was beaten by knockout in the fourth round," he said. "He was knocked down three times before the referee stopped the contest. He will guarantee a good fight because Japanese boxers don't give up easily and they fight with a lot of spirit. "Rex left for the Philippines last Sunday and will be there for about six weeks before he returns on May 24. The fight purse is US$30,000." Lau said Tso stood a good chance, but he wasn't entirely happy with the Wonderkid's last fight against Matsuyama. "His close combat fighting has to improve. That's one of the things we have to work on," he said. "Last time, Rex was pushed into a corner and was punished. He has to use his footwork and get back to the centre of the ring instead of taking all the punches against the ropes. He has to improve toe-to-toe. "Kakutani is a good fighter. He actually fought for the Japanese super-flyweight title in 2012 and narrowly lost by a split decision [10 rounds] against the six-time Japanese super flyweight champion Teiru Kinoshita. There's no doubt he's a tough fighter."