Kerber's quick exit a sign of the times

NEW YORK - Angelique Kerber said on Tuesday her two stints as world No 1 had made for an uncomfortable existence as her mediocre season hit a new low with a first-round exit at the US Open.

Sixth seed Kerber was defeated 6-3, 6-1 by Japanese teenager Naomi Osaka, becoming the first defending champion in New York to exit in the opening round since Svetlana Kuznetsova in 2005.

The German left-hander became No 1 for the first time after winning the 2016 US Open title, but handed the crown back to Serena Williams when the American star won the Australian Open in January.