Floyd Mayweather Jr celebrated his return to the ring 21-months after dealing British boxer Ricky Hatton his first pro defeat with a unanimous points victory over Mexican Juan Manuel Marquez in Las Vegas. Widely regarded as the best defensive fighter of his generation, the American dominated all 12 rounds against his smaller opponent with his left jab and agile movement to improve his career record to 40-0 with 25 knockouts. Mayweather, who held a significant weight and reach advantage over five-times world champion Marquez, was a heavy favourite going into the non-title bout at the MGM Grand Garden Arena and knocked down Marquez in the second round. Lightning The 32-year-old showed no sign of rust after his lengthy stint away and controlled the pace of the fight with his lightning hand and foot speed, rock-solid defence and a series of telling combinations. "I've been off for almost two years but it felt really good to be back," Mayweather said ringside on Saturday night. "I was happy with the victory but I know can get better." The flamboyant American was back in the ring for the first time since his 10th round stoppage of Hatton at the same venue in December 2007. "That guy is tough as nails," said Mayweather, who gained one-sided verdicts from all three judges -- by 118-109, 120-107 and 119-108. "He was a great little big man. I threw a hell of a shot that dropped him, and then he got back up and kept fighting." The 36-year-old Marquez, who moved up two weight classes to challenge the American, slipped to 50-5-1 with 37 knockouts. Hurt once "He surprised me with the knockdown. He hurt me in that round but not at any other time," said the Mexican who had never fought above 135 pounds. "I don't want to make excuses but the weight was the problem," added Marquez, who was four pounds lighter at Friday's weigh-in. "He's too fast. When I hit him he laughed but I knew he felt my punches. I did the best I could do." "He's too fast. When I hit him he laughed but I knew he felt my punches" Mexican boxer Juan Manuel MarquezWatched by a crowd of 13,000 that included basketball great Magic Johnson and boxers Oscar De La Hoya and Bernard Hopkins, Mayweather belied his lengthy absence from the ring by making a strong start. He landed a couple of left jabs early on, drawing blood on his opponent's forehead before Marquez ended a fast-paced opening round by pinning the American against the ropes. Although Marquez forced Mayweather to back-peddle in the early exchanges in round two, the confident American put the Mexican on the canvas with a stinging left hook. Mayweather, moving nimbly and frequently leaning back to avoid head punches by Marquez, took advantage of his longer reach to dominate the next three rounds. While the aggressive Marquez frequently drove Mayweather on to the ropes, the ever-smiling American repeatedly landed telling left jabs to remain in overall control. Mayweather ended the 11th round by landing a crunching right hook and maintained control until the final bell sounded to end the 12th. The American dominated the official statistics, connecting with 290 of 493 punches thrown to 69 of 583 for Marquez. He also landed 105 power punches compared to the Mexican's 48.