Djokovic advances but new concerns rise over fitness

By Steve Keating NEW YORK (Reuters) - Novak Djokovic opened the defence of his U.S. Open title with a 6-3 5-7 6-2 6-1 win over Poland's Jerzy Janowicz on Monday, but the laboured performance gave rise to fresh concerns about the world number one's fitness. After a sizzling start to the season that brought grand slam wins No.11 and 12 at the Australian and French Opens, Djokovic's form has plummeted, with a third-round loss to Sam Querrey at Wimbledon followed by a first-round exit at the Rio Olympics. The Serb might have been in trouble on another day at Flushing Meadows but Janowicz, ranked 246 places below Djokovic, has advanced from the first round just once in four previous U.S. Open visits and looked unlikely to do it again on Monday.