Nick Kyrgios claimed umpire Mohamed Lahyani's controversial pep talk at the US Open had no impact on his improvement in his come-from-behind victory over Pierre-Hugues Herbert.

The erratic Kyrgios lost the opener 6-4 and was trailing 0-3 in the second set when Lahyani left his chair at the changeover and told the Australian: "I want to help you."

According to a statement later released by the US Open, Lahyani went down to Kyrgios due to the crowd noise and warned him over his apparent lack of interest in proceedings as well as advising him on possible medical assistance.

Kyrgios would lose just six games thereafter as he progressed 4-6 7-6 (8-6) 6-3 6-0 to set up a third-round tie with five-time champion Roger Federer.

Asked about what Lahyani said to him, Kyrgios replied: "He said he liked me. I'm not sure if that was encouragement. He just said that it's not a good look.

"I wasn't feeling good. I know what I was doing out there wasn't good. I wasn't really listening to him, but I knew it wasn't a good look. It didn't help me at all."

Herbert felt there was no need for Lahyani to leave his chair to talk to Kyrgios, even if the Australian claimed it had no impact on his performance.

"I don't think he has to go down and take the position of a coach, like you see on the WTA Tour," Herbert said. 

"I don't know yet if it would have changed something. I just know he doesn't have to do that."