Hillary Clinton has been hailed as one of America's great secretaries of state by President Barack Obama, who said he was "going to miss" his former political rival after she stepped down next week.Mr Obama used his first – and probably last – joint interview with Mrs Clinton, as an opportunity "to publicly say thank you" for her four years of exhausting work as America's most senior diplomat. "I think Hillary will go down as one of the finest secretaries of state we've had," said Mr Obama, who added: "I want the country to appreciate just what an extraordinary role she's played". The president said that the pair had created "a great collaboration" since she accepted a place in his Cabinet following her defeat to Mr Obama in the 2008 Democratic presidential primary contest. "I'm going to miss her," he told CBS. "I wish she was sticking around. But she has logged in so many miles that I can't begrudge her wanting to take it easy for a little bit". Mrs Clinton, who is expected to be replaced by Senator John Kerry, conceded that their partnership was "improbable" after the bruising primary campaign, which featured furious rows between their camps.She even suggested that she had developed a routine answer for sceptical foreign officials to "help them understand" how the two could work together effectively after such a bitter rivalry. "I say, 'look: in politics and in democracy, sometimes you win elections and sometimes you lose elections. And I worked very hard, but I lost. And then President Obama asked me to be secretary of state and I said yes'. And why did he ask me, and why did I say yes? Because we both love our country".