MELBOURNE, Australia — John Isner moved the United States into the quarterfinals of the Davis Cup World Group, defeating Australia's Bernard Tomic 6-4, 6-4, 5-7, 7-6 (4) on Sunday for a winning 3-1 edge in the first-round tie on grass at Kooyong.
Isner, who beat Sam Groth on Friday in the opening singles match, appeared to sustain an upper left leg injury early in the second set. In the 12th game of the third set, he saved four set points before Tomic sent it to a fourth set when Isner netted a backhand.
The big-serving American finished the match with a service winner and ace, one of his 49 in the match.