New York - Roger Federer said respected umpire Mohamed Lahyani was wrong to get out of his chair to give Nick Kyrgios a controversial pep-talk at the US Open on Thursday which sparked a row over impartiality of officials in the sport.
WATCH: Tennis umpire tells bad boy Kyrgios to try harder
Lahyani stunned fans when he climbed down from his chair in the second set of Kyrgios's second round match against Pierre-Hugues Herbert of France on Court 17 to seemingly berate the Australian for a lack of effort.
"I want to help you. This isn't you. I know that. You are great for tennis," Lahyani can be heard saying.
Kyrgios was trailing by a set and 3-0 at the time, but went on to pocket 19 of the next 25 games to win 4-6, 7-6 (8/6), 6-3, 6-0, setting up a third round clash with five-time US Open champion Federer on Saturday.
"It's not the umpire's role to go down from the chair. But I get what he was trying to do. He behaves the way he behaves," said Federer.
"You as an umpire take a decision on the chair, do you like it or don't you like it. But you don't go and speak like that, in my opinion.
"I don't know what he said. I don't care what he said. It was not just about 'How are you feeling? Oh, I'm not feeling so well'. Go back up to the chair. He was there for too long.
"It's a conversation. Conversations can change your mindset. It can be a physio, a doctor, an umpire for that matter. That's why it won't happen again. I think everybody knows that."
Kyrgios played down the incident, claiming Lahyani had merely said "he liked me" and that "he was just concerned with the way I was playing".
Like Federer, Herbert insisted that Lahyani had over-stepped the mark and would confront the official over the issue.
US Open results on Thursday, the fourth day of the 2018 tournament at Flushing Meadows (x denotes seeded player):
Marin Cilic (CRO x7) bt Hubert Hurkacz (POL) 6-2, 6-0, 6-0
Alex De Minaur (AUS) bt Frances Tiafoe (USA) 6-4, 6-0, 5-7, 6-2
Jan-Lennard Struff (GER) bt Julien Benneteau (FRA) 6-2, 4-6, 6-1, 3-6, 6-3
David Goffin (BEL x10) bt Robin Haase (NED) 6-2, 6-7 (1/7), 6-3, 6-2
Diego Schwartzman (ARG x13) bt Jaume Munar (ESP) 6-2, 6-0, 5-7, 6-2
Kei Nishikori (JPN x21) bt Gael Monfils (FRA) 6-2, 5-4 - retired
Philipp Kohlschreiber (GER) bt Matthew Ebden (AUS) 6-7 (1/7), 6-3, 6-2, 6-0
Alexander Zverev (GER x4) bt Nicolas Mahut (FRA) 6-4, 6-4, 6-2
Novak Djokovic (SRB x6) bt Tennys Sandgren (USA) 6-1, 6-3, 6-7 (2/7), 6-2
Richard Gasquet (FRA x26) bt Laslo Djere (SRB) 6-3, 7-6 (7/5), 6-3
Lucas Pouille (FRA x17) bt Marcos Baghdatis (CYP) 6-7 (4/7), 6-4, 6-4, 6-3
Joao Sousa (POR) bt Pablo Carreno Busta (ESP x12) 4-6, 6-3, 5-7, 6-2, 2-0 - retired
John Millman (AUS) bt Fabio Fognini (ITA x14) 6-1, 4-6, 6-4, 6-1
Mikhail Kukushkin (KAZ) bt Chung Hyeon (KOR x23) 7-6 (7/5), 6-2, 6-3
Nick Kyrgios (AUS x30) bt Pierre-Hugues Herbert (FRA) 4-6, 7-6 (8/6), 6-3, 6-0
Roger Federer (SUI x2) bt Benoit Paire (FRA) 7-5, 6-4, 6-4
Caroline Garcia (FRA x6) bt Monica Puig (PUR) 6-2, 1-6, 6-4
Carla Suarez Navarro (ESP x30) bt Kristina Mladenovic (FRA) 6-1, 4-6, 6-4
Maria Sharapova (RUS x22) bt Sorana Cirstea (ROM) 6-2, 7-5
Jelena Ostapenko (LAT x10) bt Taylor Townsend (USA) 4-6, 6-3, 6-4
Madison Keys (USA x14) bt Bernarda Pera (USA) 6-4, 6-1
Aleksandra Krunic (SRB) bt Kirsten Flipkens (BEL) 6-1, 6-3
Dominika Cibulkova (SVK x29) bt Hsieh Su-Wei (TPE) 7-6 (7/3), 4-6, 6-4
Angelique Kerber (GER x4) bt Johanna Larsson (SWE) 6-2, 5-7, 6-4
Petra Kvitova (CZE x5) bt Wang Yafan (CHN) 7-5, 6-3
Aryna Sabalenka (BLR x26) bt Vera Zvonareva (RUS) 6-3, 7-6 (9/7)
Naomi Osaka (JPN x20) bt Julia Glushko (ISR) 6-2, 6-0
Aliaksandra Sasnovich (BLR) bt Darya Kasatkina (RUS x11) 6-2, 7-6 (7/3)
Kiki Bertens (NED x13) bt Francesca Di Lorenzo (USA) 6-2, 6-1
Marketa Vondrousova (CZE) bt Eugenie Bouchard (CAN) 6-4, 6-3
Katerina Siniakova (CZE) bt Ajla Tomljanovic (AUS) 6-3, 6-7 (3/7), 7-6 (7/4)
Lesia Tsurenko (UKR) bt Caroline Wozniacki (DEN x2) 6-4, 6-2