Swiss maestro Roger Federer, who recently lifted his 19th Grand Slam champion at the age of 35 at Wimbledon, has insisted that it would be a joke if he wins third slam this year at the US Open.Federer has had a sparkling 2017, having emerged victorious in five tournaments including his fifth Australian Open title in January and a record eighth-Wimbledon title this month.The current world number three, who has returned to his menacing best, also holds a great chance to grab final slam of the year-US Open-which he won five times between 2004 and 2008.However, Federer refuses the possibility of accomplishing the same, saying, “That would be a joke, if I won three slams this year out of nowhere. I know if I stay in shape, there are chances for me to do well at the US Open, but to win it? Yeah, at some stage I almost feel like I have to be realistic.””I am not 25 anymore. I’m not sure I can win three slams in one year. Winning two is already pretty crazy and plenty good enough for me,” Federer told in an interview with CNN.The Swiss legend, however, said that he would try and give his best shot in the final major of the season.”I’ll definitely try and get myself organised, prepared and ready so that I’ll have the best chance to do well at the US Open,” he added.Earlier this month, Federer outclassed Marin Cilic of Croatia 6-3, 6-1, 6-4 in his 11th final at the All England Club.advertisementThe victory made Federer the oldest man to win at the All England Club in the Open era, which began in 1968.With Federer’s fifth crown of the year, the Swiss also surged to No. 3 – his highest rankings position since August 2016.