"The disappointment with Kyrgios is when he doesn't compete hard enough.
"We saw in his opening two rounds how good he can be when he competes well, but when he doesn't I don't like it."
His loss continues his damning record at Grand Slams, having never made it past the third round at the US Open, or the quarter-finals of any slam.
Despite showing just how damaging he can be in his opening two games, Kyrgios failed to fire against Rublev as he continued to complain about being unable too see.
The trainer was called early in the match as the mercurial Aussie continually put eye drops in throughout the contest.
In the middle of the opening set Kyrgios took aim at a linesman who approached the chair umpire mid-game to report the fiery star for an audible obscenity.
"What, that's all right. What did I say?" Kyrgios asked.
He then turned to the linesman and asked him to "come tell me what I said" before shouting "whistleblower".
The chair umpire advised Kyrgios he had reported a word he'd said to which Kyrgios responded "which word was it? I said I can't see a thing, that's all I said".
Things didn't get any better in the second set for Kyrgios as he kept telling his coaching box of his eyesight struggles.
"Call of Duty has ruined me, I can't see a thing," Kyrgios said to his box.
He then escalated his complaints midway through the second set as he was picked up saying:
"I don't want to be here though. I just want to go home".
Rublev's victory made sure of that.
