Double Olympic champion flyweight Zou Shiming of China works out in front of the media at the Venetian Macao hotel in Macao March 5, 2015. [Photo/Agencies]

Zou Shiming waited until his 30s to begin his professional boxing career, and he has been in a hurry ever since.

In just his seventh pro fight, China's double Olympic gold medalist will attempt to claim the IBF flyweight title belt this weekend.

Although Zou is an underdog in many boxing observers' minds when he meets Thailand's Amnat Ruenroeng on another big-money card in Macao, Zou and his promoters are eager to justify his enormous popularity with a championship.

Zou is still learning to fight like a professional under trainer Freddie Roach, who has attempted to rebuild Zou's slick amateur fighting style into a durable pro skill set. But with his 34th birthday looming this month, Zou didn't want to wait any longer to test himself against the best.

"I am very calm, not nervous," Zou said through a translator in Los Angeles recently. "I have been prepared for this moment for a long time. I am focused on myself, on executing Freddie's game plan. I felt a lot more pressure when I was in the Olympics. This time, the pressure is on Ruenroeng."

Zou's success has been the main reason for the growing popularity of boxing in China. His fight at the Cotai Arena in the opulent Venetian Macao will be available to more than 1 billion potential viewers in a nation where the sport was banned until the 1980s.