Even legends have regrets! King Roger, aka FedEx, just admitted the 2009 US Open final loss to Delpo still haunts him. He was riding a 40-match win streak at Flushing Meadows, but back pain and missed chances let the Tower of Tandil snatch the title. Federer says this one stings more than even his epic Wimbledon heartbreaks against Rafa and Novak. Which loss do you think hurt most for the Maestro? #Sports #Tennis #Federer