Washington - New US number one John Isner, who took
back-to-back titles the past two weeks in Newport and Atlanta, withdrew from
the ATP Citi Open on Monday with a right knee injury.
The 32-year-old standout, a three-time runner-up at the
Washington hard-court event, won the 11th and 12th titles of his career over
the past two weeks, downing Australian Matthew Ebden on Newport grass and
compatriot Ryan Harrison in two Atlanta tie-breakers in the finals.
But the toll prompted Isner to withdraw from Washington,
where he was seeded ninth and owned a first-round bye, as Masters Series events
in Montreal and Cincinnati loom before the US Open starts August 28.
The twin triumphs were enough to boost Isner over Jack Sock
in the rankings to top the American list, Isner moving to 18th this week with
Sock staying at 19th.
Isner's departure leaves only nine of the world's top 20
players at the US Open tune-up event in the US capital.