Rising Mexican star Saul "Canelo" Alvarez reckons his World Boxing Council super welterweight title defence against US veteran Shane Mosley on Saturday is the start of bigger things. "This is another test, another gate that I have to walk through," Alvarez said. "With Mosley being who he is, I feel that I have entered the big leagues. "There will be way bigger fights and better things for me." Mosley, a 40-year-old warrior, says Alvarez won't find it so easy to walk through him, even if his last six fights included three defeats and a draw -- and unimpressive efforts against Manny Pacquiao and Floyd Mayweather. "They're saying they're going to walk through the doors, but there's going to be a big toll to pay," said Mosley, who brings a record of 46-7-1 with 39 knockouts to the bout, which is on the undercard of the World Boxing Association super welterweight title bout between Puerto Rican champion Miguel Cotto and unbeaten American Floyd Mayweather. "Talking about a stepping-stone and a guy they're going to walk over, they're going to pay a hefty price. And that hefty price is going to be in the ring." Alvarez will be making the fourth defence of the title he captured in March of 2011 with a unanimous 12-round decision over Britain's Matthew Hatton. He followed up that victory for the vacant belt with wins over Ryan Rhodes, Alfonso Gomez and Kermit Cintron. The 21-year-old is unbeaten with 39 victories and one draw and 29 wins inside the distance. He says far from taking Mosley for granted, "I'm prepared for the best Mosley ever." "He is a complete fighter. He's fast, he's strong," Alvarez said. "I have never faced anybody like him. "The key in this fight for me is not to get desperate. I have to take my time and stick to my game plan."