Bernard Tomic accuses Nick Kyrgios of faking illness

Frustrated and hampered by a wrist problem, Bernard Tomic launched a surprising attack on unwell Davis Cup team-mate Nick Kyrgios, overheard saying "bulls*** he's sick" during his loss to John Isner.

Kyrgios withdrew from the first-round tie against the United States due to a virus, replaced by retired Australia captain Lleyton Hewitt in Melbourne.

And as Tomic struggled against Isner, who 6-4 6-4 5-7 7-6 (7-4) to lead the USA into the quarter-finals via a 3-1 victory, the 23-year-old accused his countryman of faking illness at the change of ends in the third set on Sunday.

"Nick's sitting down in Canberra. Bulls*** he's sick," Tomic could be overheard saying by the courtside microphones.

"Two times he's done it. Two times he's faked it," Tomic added, seemingly in reference to Kyrgios' withdrawal from Australia's World Group opener against Czech Republic last year.

Tomic managed to regain his composure afterwards, rallying to force a fourth set, having seen Isner save four set points in the third.

Isner, however, was not to be denied, setting up a quarter-final against either Croatia or Belgium after firing down his 49th ace of the match.