"I'm trying my nuts off, and when I try my nuts off, f**k my knee starts hurting.
"At this stage, I can't even rock back on my serve, man."
Kyrgios later declared that "it hurts to walk" and "I've just given up basically".
"I've taken four tablets and it's gotten worse. It's f**king terrible. By this stage, it's f**ked. It feels like dogs**t, mate. Absolute dogs**t," he told the trainer.
Following the loss Kyrgios showed tepid support for under siege Aussie Davis Cup captain Lleyton Hewitt while also announcing he is not upset that Bernard Tomic declared he has issues with Hewitt's captaincy.
Kyrgios saved his best performance of the night for his media conference where he largely sidestepped prickly questions.
Kyrgios said he hadn't seen Tomic's explosive accusations against Hewitt, which included a claim that both Kyrgios and Thanasi Kokkinakis do not want to play for the former two-time grand slam champion.
When asked directly if there is a rift between himself and Hewitt, Kyrgios replied: "Not really".
When asked about Tomic's declaration that Kyrgios doesn't want to play for Hewitt, Kyrgios was again unconvincing in his support of Hewitt.
"I don't know what to say," he said.
"I don't have a big deal with anything. I always want to play Davis Cup. I love playing Davis Cup."
He said he is not "upset" towards Tomic for dropping his name.
When asked if he supports Hewitt's captaincy continuing, Kyrgios said with a bored shrug of his shoulders: "Sure".
Kyrgios also said he will make himself available for the next Davis Cup tie, but conceded he may not be picked after his rankings slide.
"I don't think I'd be picked though," he said.
"There's a lot of good players right now. Alex de Minaur, (John) Millman, they're all playing great. There's a lot of depth which is pretty good for us."
Having been unable to defend his ATP Tour Rankings points from his fourth round appearance at last year's Open, Kyrgios is expected to slide outside the top 70.
- with news.com.au