-LRB- CNN -RRB- -- He has met the United States ' former First Lady , and an audience with Barack Obama awaits , but the American that world champion boxer Amir Khan really wants to face next is proving a bit more elusive . The British fighter has set his heart on becoming the planet 's best pound-for-pound pugilist , and for him that means taking on the undefeated Floyd Mayweather Jr. -- who , as a five-division champion , once laid claim to that coveted crown . Khan , 24 , unified the WBA super and IBF light welterweight world championship belts in July by defeating American Zab Judah in Las Vegas in July , while Mayweather recently returned to the ring after a 16-month absence . Six-time world champion Mayweather has won all of his 42 fights as a professional , 26 by knockout , and emerged victorious from a controversial contest with Victor Ortiz on September 18 . But the fight many boxing fans want to see is Mayweather against eight-division champion Manny Pacquiao -- the Filipino rated by Ring Magazine as the best pound-for-pound boxer in the world . `` Floyd Mayweather pound for pound is probably one of the best fighters in the world , '' Khan , who won an Olympic silver medal in the lightweight category at the Athens Games in 2004 , told CNN . `` Me and Manny both want to fight him , but that will never happen because at the moment he does n't want to fight either of us . But it will come to a stage when the pressure will be so much on Floyd Mayweather that he 'll have to take the fight . '' Khan doubts that a match-up between his Golden Boy stablemate Mayweather and Top Rank 's Pacquiao will ever happen , with disagreements over drug-testing and money having previously prevented the fight . `` You 've got two different promotion teams , and for them to agree on terms for a fight is very difficult , '' he said . `` Firstly , you 've got Mayweather saying that Manny has to take so many drug tests and blood tests , then Manny talking about the purse . But that fight will generate about $ 100 million each , so it 's a lot of money to say no to . '' Mayweather , 34 , and Pacquiao , 32 , have both occupied the position of best pound-for-pound boxer in the world , and Khan is aiming to emulate the success enjoyed by the decorated duo . `` I want to be known as a legend in the sport and I want to win everything . I want to be a pound-for-pound champion of the world , and every morning when I wake up that 's what drives me to the gym to train hard , '' he said . `` When I 'm tired in the gym , that 's what pushes me , because I want to be the best there is . And , I 'm nearly there . I 'm only 24 , I 'm the unified champion , I 'm a two-time world champion , and I 've done it so young . But I want to achieve more . '' Khan has seen his international profile increase in the last 18 months , having fought in the U.S. on three occasions since making his American bow against Paulie Malignaggi at New York 's Madison Square Gardens in March 2010 . It would now appear even politicians are starting to sit up and take notice of the Bolton-born fighter , with Khan having recently met U.S. Secretary of State Hilary Clinton and now being lined up for an audience with President Barack Obama later this year . `` I was invited to go to the state building , '' said Khan . `` Hilary Clinton invited me and my team . It was an honor to be part of that event . It was about the Muslim sportsmen who were influential and who do good things in the Muslim community . `` I enjoyed it and they want me back over there in December probably to meet Obama , so it 's good times . `` When they first got talking about it , I thought they were just pulling my leg , but they were quite serious about it , and I thought ` Wow ' . I might never get the chance to go to the White House or meet Obama again , so I 'm going to make the most of it . ''