Federer's loss to Kokkinakis was his second in six days, after falling to Juan Martin del Potro at Indian Wells. Kokkinakis is the lowest-ranked player to defeat a men's world No 1 since 178th-ranked Francisco Clavet beat Lleyton Hewitt in Miami 2003, the ATP Tour said on its website.
Roger Federer this evening:#MiamiOpen ? Back-to-back defeats for the first time since 2014 ? Will relinquish number 1 ranking at end of the tournament ? Announces decision not to play the French Open pic.twitter.com/iLCC9NWe6r — BBC Tennis (@bbctennis) March 24, 2018