BERNARD Tomic’s has taken a potshot at absent teammate Nick Kyrgios during a frustrating Davis Cup struggle with John Isner.

The Queenslander was heard on courtside microphones snapping at Hewitt about Kyrgios’ absence during a changeover late in the second set.

“Nick’s sitting down in Canberra. Bulls**t he’s sick,” Tomic was overheard telling Hewitt as the match looked to be slipping away.

WATCH TOMIC’S BIZARRE KYRGIOS SLEDGE IN THE VIDEO PLAYER ABOVE

Bernard Tomic receives medical attention in his match against John Isner. Source: Getty Images

Kyrgios was ruled out of the tie because of a virus, leaving Tomic, Hewitt, Sam Groth and John Peers to face higher-ranked opposition.

Tomic’s mood was not helped by wrist soreness and rampant Isner’s form.

The Gold Coaster could barely impact on Isner’s serve as the match - and the tie - appeared to be running quickly out of Australia’s control.

Tomic and Kyrgios are close friends, making Tomic’s remark all the more surprising.

VIDEO: TOMIC GOES DOWN IN FOUR TO ISNER

Tomic muttering angrily about Kyrgios' absence during a changeover, but hanging in this third set, keeping Isner very off-balance. 6-5*. — Ben Rothenberg (@BenRothenberg) March 6, 2016

Wow, interesting. Tomic to Hewitt at sitdown: "Nick's sitting down in Canberra. Bullshit he's sick." #DavisCup #AUSUSA — Marc McGowan (@McGowan_NTNews) March 6, 2016

Tomic's head elsewhere at the moment. At sit down, Tomic heard saying "Nick sitting down in Canberra. Bullshit he's sick" @shanemcinnes — Craig Moore (@Moore17C) March 6, 2016

Tomic's comment "That's twice he's done it" relating to Kyrgios withdrawing from Davis Cup squad in Feb 2015 ahead of tie v Czech Republic — Shane McInnes (@shanemcinnes) March 6, 2016

Tomic also said to Hewitt: “Two times he done it. Two times he’s faked it”, likely referring to Kyrgios’ withdrawal from Australia’s 2015 World Group opener against Czech Republic in Ostrava.

World No.20 Tomic managed to pull himself together to take the third set against Isner but lost the fourth set in a tiebreak to lose the match, and hand the US an unbeatable 3-1 lead in the tie.