Spain\'s two-time Tour de France champion Alberto Contador stands tantalisingly close to a stunning win in the Tour of Spain, his first major Tour since returning from a two year doping ban. However, while the 29-year-old - who still protests his innocence over the minute trace of clenbuterol found in his urine on the 2010 Tour de France - is just 28 seconds behind overall leader Joaquim Rodriguez he admits it will be tough for him to claw the deficit back. Rodriguez - who suffered heartbreak in this year\'s Tour of Italy ending up second overall having entered the final stage in the lead - extended his overall lead over Contador by six seconds during Monday\'s 16th stage and is now within striking distance of securing his first ever major Tour win. \"I am in second place now and would like to exchange it for first place, but I am aware of how difficult it will be to win,\" Contador told a news conference in the northern city of Comillas during the second rest day of the race. \"It is complicated because there is not much more ground to cover, but every day there will be possibilities in the Tour to catch up. \"I am going to give all I have no matter what result I have, I have my own racing style and it does not even occur to me to do anything but to try to win.\" Rodriguez, 33, fended off a series of attacks from Contador during the steep final climb of the 16th stage -- a 183.5 kilometres mountain ride from Gijon to Cuitu Negru in northern Spain -- to finish third. \"I have analysed where I can improve and one thing is clear I am not in my usual shape,\" Contador said. \"But you have to recognise that \'Purito\' (Rodriguez\'s nickname) is in incredible shape, which is making everything harder,\" he added. The Tour is Contador\'s first major cycling race since his two-year drugs ban ended on August 6. He said he was happy to see so many fans cheering him on along the route of the race. \"I am really satisfied, I feel in debt to all the fans, the affection and support they have given me has been incredible,\" said Contador. The Spanish rider has always insisted that the trace of the banned substance clenbuterol came from a contaminated steak he ate on the eve of the test. The Tour continues on Wednesday with a 187.3-kilometre ride between Santander and Fuente De, a second category mountain climb.