Unbeaten Hong Kong star Rex Tso Sing-yu has been warned by his trainer to be on "extra guard" when he fights on the undercard of the "Clash in Cotai" in Macau. Tso is aiming to stretch his record to 11 straight wins as he takes on Thai youngster Susu Sithjadeang (7-3) in a six-round, non-title super-flyweight contest on November 24. "I have been warned by my trainer, Jay Lau [Chi-yuen], not to take my next opponent lightly. It's the first time in a long time that I will fight somebody younger than me and this could be a real challenge," Tso said. "Susu is 22 years old and he's hungry. His stamina and endurance will probably match mine, so he could prove a handful." Tso, 26, has won six of his fights inside the distance. "The last time I fought somebody younger than me was in my first professional fight two years ago. Youngsters go into the ring thinking they have nothing to lose and they throw more punches and attack more. I have to be on the look out." Lau said the Tso camp would start intensive training in the Philippines on September 30 through to November 10. He will complete most of his preparations in Manila under Filipino trainer Aljoe Jaro. Tso will also spend two weeks training at General Santos in the Philippines in the Manny Pacquiao camp next month. "It's going to be a good, tough fight for Rex. I told him to be careful of Susu, who has a very good heart and surely wants to beat Rex, who is well known in Thailand because he has fought some good Thai fighters," Lau said. Tso will be fighting for the first time since his unanimous victory over another Thai, Rusalee Samor, in Fists of Gold II in July. The bout will serve as a warm-up for a second title defence of his World Boxing Council (WBC) ABCO Asia Continental title in Monaco on January 7. "I have never been in Europe before and it's going to be a real experience fighting in Monaco," Tso said. The November fight will be on the undercard of the main event between Philippines superstar Pacquiao and American Brandon Rios. The undercard will also feature four fights starring Chinese boxers, with golden boy Zou Shiming out to extend his winning streak to three. Undefeated mainland professional Yang Lianhui (12-0, 8 KOs), who is training in the United States under the care of Hall of Fame coach Freddie Roach, will make his Macau debut and Macau's light middleweight Ng Kuok Kun will be chasing his second professional win. Their opponents are yet to be named.