Roger Federer is doing his utmost to treat himself to one last ride before retiring. The Swiss champion had tried a timid comeback last year, but things hadn’t gone well. Suffice it to say that the King played just 13 official matches in 2021, collecting nine wins and four losses.The round of 16 at Roland Garros and the quarterfinals at Wimbledon were his best seasonal results, a far too meager booty for a legend of his caliber. A few weeks after the Championships, the former world number 1 announced that he had suffered a relapse in his right knee and h …