World welterweight champion Manny Pacquiao believes a showdown against Floyd Mayweather Jr. will happen eventually despite hard feelings over drug-testing demands that aborted negotiations. “I believe the fight will happen some other time,” Pacquiao told reporters Wednesday. “It will happen.” Pacquiao spoke about Mayweather and the failed talks for a Las Vegas clash after a Madison Square Garden news conference to promote his March 13 WBO title defense in Dallas against former champion Joshua Clottey of Ghana. Mayweather had demanded Olympic-style, random blood testing for a showdown between the two best pound-for-pound boxers in the world - a testing protocol beyond what is required by the Nevada State Athletic Commission. Pacquiao said testing too close to the fight might have interrupted his training and left him weak for the bout. “I'm honest, and a clean fighter,” Pacquiao, 31, said. The Filipino said the undefeated Mayweather's drug-testing demands unfairly cast him in a bad light as a suspected cheat. “It's not true. He's accusing me,” Pacquiao said. “I want to clear my name because I'm a very honest person. I'm very disappointed for what he accused me of. I'm clean. I'm not cheating. I'm a very honest fighter.” Pacquiao, who won the welterweight crown from Miguel Cotto in November to become the first boxer to win titles in seven different weight classes, said he hoped to get in the ring with Mayweather before the year was out. “I'm still hoping the fight will be pushed through, maybe by summer time,” he said. “It would be a good fight if it happened.” Freddie Roach, Pacquiao's trainer, shared the fighter's optimism that a Mayweather fight could still be arranged. “I think it's going to happen,” Roach told reporters. “I think it's likely.” Roach said Mayweather's camp had accepted a compromise that would allow for blood testing up to 14 days before the fight and immediately afterwards, but that Mayweather had rejected that. “We're not going to sit around and wait for this guy,” Roach said. “Manny was really excited about that fight,” said Roach. “Hopefully it will happen some day.”