Trash talking from Bernard Tomic and Nick Kyrgios has overshadowed Australia's premature exit from the Davis Cup for another year.

As Tomic was questioning Kyrgios's commitment to the competition on Sunday, his absent teammate was at home in Canberra questioning the credentials of an American journalist who urged Lleyton Hewitt not to play himself if Australia's first-round tie with the USA went to a deciding fifth rubber.

Kyrgios defended his first-year Cup captain on Twitter: "Ben Rothenberg could be the worst writer to exist. Sit the fk down mate".

The 20-year-old's spray comes less than a fortnight after the expiration of his six-month suspended ban for sledging French Open champion Stan Wawrinka at last year's Montreal Masters.

But Kyrgios was on the end of his own lashing hours later from Tomic.

Irritated during his reverse singles loss to John Isner, Tomic was heard on Channel 7 muttering to Hewitt: "Two times. Two times he's faked it. Two times Nick has faked it. Twice. While I'm here, Nick's sitting down in Canberra. Bullsh*t he's sick."

Tomic later said he'd lose respect for Kyrgios if he played the next ATP tour event after pulling out of Australia's first-round tie against the United States in Melbourne this weekend.

Tomic said he played with a wrist injury and questioned the legitimacy of the virus that ruled out Kyrgios if he was able to compete so soon after.

Tomic said he spoke to his teammate after his loss and Kyrgios told him he was planning to play in Indian Wells, California, this week.

The Australian No.1 said a similar situation happened last February when Kyrgios withdrew from the Davis Cup against the Czech Republic.

"He didn't come to Czech and had stress fractures and somehow played Indian Wells and felt good," Tomic said at the post-match press conference.

"Now it's going to be funny for me to see whether he plays.

"If he plays Indian Wells, then he's definitely lost a little bit of my respect."

He said all he wanted was for Kyrgios to give his all to Australia.

"It's just disappointing to not have him here," Tomic said.

"He's an amazing player and it would have been important to have him here."