MELBOURNE, Australia (AP) -- The court surface didn't make a bit of difference to the United States - its Davis Cup team is through to the quarterfinals.

John Isner defeated Australia's Bernard Tomic 6-4, 6-4, 5-7, 7-6 (4) on Sunday to clinch a 3-1 victory in the World Group first-round tie on grass at Kooyong.

Based on an agreement between the countries and the International Tennis Federation, that surface was supposed to be hardcourt. Although all three groups involved forgot about the deal forged in 1999, Isner, the Bryan brothers and Jack Sock made sure it didn't matter.

Isner, who beat Sam Groth on Friday in the opening singles match, finished the match against Tomic with a service winner and ace.

The scheduled reverse singles match between Groth and Sock was not played.

The Americans will next host the winner of Croatia and Belgium in the quarterfinals. Croatia leads that series 2-1 going into Sunday's reverse singles.

Bob and Mike Bryan beat Australia team captain Lleyton Hewitt - who came out of a 41-day retirement - and John Peers 6-3, 6-3, 4-6, 4-6, 6-3 in doubles to put the Americans in front on Saturday.

Hewitt, who retired for the first time at the Australian Open in January, had replaced an ill Nick Kyrgios in the Australian squad but didn't play in either of the opening singles. On Friday, Isner beat Groth and Tomic defeated Sock to leave the tie level at 1-1 after the first day.

''It was incredible tie for us,'' Isner said. ''We knew Australia was going to be tough and they put up a great fight.''

U.S. captain Jim Courier added: ''Our team came good. John stepped up today.''

On Sunday, during the match, Tomic appeared to take issue with Kyrgios' absence due to a virus.

Midway through the second set and struggling against Isner, Tomic was heard on courtside microphones telling Hewitt during a changeover: ''Nick's sitting down in Canberra ... he's sick ... two times Nick's done it.''

After the match, Tomic left no doubt he was upset with Kyrgios, saying he will lose respect for his Davis Cup teammate if he plays the next ATP tour event.

''He didn't come to Czech (Republic, last year) and had stress fractures and somehow played Indian Wells and felt good,'' Tomic said. ''If he plays Indian Wells, then he's definitely lost a little bit of my respect.''

Hewitt defended Krygios.

''Nick came down here and gave everything he had to try to be available and there's no doubt he was sick,'' Hewitt said.

Ahead of Saturday's doubles, the court surface became controversial when the ITF admitted that the Kooyong matches should have been played on hard courts, not grass.

In 1999, the last time Australia and the U.S. met in the Davis Cup, Australia should have hosted the matches. But a decision was made by the ITF to stage a 100th-anniversary celebration of the Davis Cup at Longwood Cricket Club near Boston, so that match was played there.

The ITF placated Australia by having it played on hard court instead of clay, which the Americans preferred. In exchange, it was agreed that the next time the two countries played in Australia, it would be on hard courts.

But that pact was somehow overlooked when Australia announced a drop-in grass court as the surface at Kooyong, the former Australian Open venue in suburban Melbourne.

''This was an oversight by the ITF, USTA and TA which all acknowledge and will refer to the Davis Cup Committee,'' the ITF said in a statement. ''While neither nation remembered the condition attached to this tie, now that it has been brought to their attention both Australia and USA, in the spirit of sportsmanship ... have agreed to accept the decision of the committee regarding surface for the future tie.''

It was the 46th time Australia and the U.S. have met in the Davis Cup. The U.S. has a leading 32 Davis Cup titles, and Australia is second with 28.