London - Nick Kyrgios was embroiled in a bizarre mid-match rules lesson as the controversial Australian blasted his way into the Wimbledon third round.
Kyrgios was in typically feisty mood during his 6-3, 6-4, 7-5 victory against Robin Haase on Thursday.
The 23-year-old received a code violation for swearing before a frank exchange of views with umpire James Keothavong.
Kyrgios had to have the foot-fault rule explained to him by Keothavong after questioning a line-judge's call.
Reacting to the call, Kyrgios said to the umpire: "What, after I hit it? How's that possible?", to which the British official responded: "That's what he has to do. He can't call it before you hit it."
Keothavong's response drew a smirk from Kyrgios and laughter from the crowd on Court Three.
Then, between sets, Keothavong got down from his chair to demonstrate the rule as Kyrgios watched on.
There was more dialogue between the pair when Kyrgios was given a code violation after being reported for his language by the line judge.
Despite the incident, Kyrgios insisted he had no problem with the foot fault call after the match.
"He told me at any point if your foot crosses the line, it's a foot fault. I mean, I just got too close to the T," he said.
But Kyrgios, who has been in hot water for his attitude on numerous occasions in the past, wasn't so forgiving of his press conference inquisitors.
Asked a question about his code violation, with a reporter suggesting he appeared upset, he replied grumpily: "Not upset at all."
When the same journalist asked why Kyrgios spoke to the umpire about it if he wasn't upset, the world number 18 said: "Because you generally talk to someone when you're curious about something. Doesn't make you upset, champ. Good question."
Quizzed on his recent fine for simulating a lewd act with a water bottle during the Queen's Club tournament last month, Kyrgios was more accepting of responsibility.
"Just stupidity. Stupidity pays a price," he said.
Kyrgios, who famously stunned Rafael Nadal at Wimbledon in 2014, has the game to thrive on grass.
But, with a tricky tie against former US Open finalist Kei Nishikori up next, he acknowledged he needs to keep his temper in check.
"It's hard for me to find the balance sometimes. When I'm in a calm place with a lot of energy, I think that's when I play my best tennis," he said.
Wimbledon results on Thursday, the fourth day of the 2018 championships (x denotes seeded player):
Philipp Kohlschreiber (GER x25) bt Gilles Muller (LUX) 7-6 (8/6), 7-6 (7/4), 7-6 (7/3)
Kevin Anderson (RSA x8) bt Andreas Seppi (ITA) 6-3, 6-7 (5/7), 6-3, 6-4
Guido Pella (ARG) bt Marin Cilic (CRO x3) 3-6, 1-6, 6-4, 7-6 (7/3), 7-5
John Isner (USA x9) bt Ruben Bemelmans (BEL) 6-1, 6-4, 6-7 (6/8), 6-7 (3/7), 7-5
Stefanos Tsitsipas (GRE x31) bt Jared Donaldson (USA) 6-3, 6-2, 3-6, 4-6, 6-3
Thomas Fabbiano (ITA) bt Stan Wawrinka (SUI) 7-6 (9/7), 6-3, 7-6 (8/6)
Karen Khachanov (RUS) bt Marcos Baghdatis (CYP) 6-3, 6-4, 3-6, 6-7 (4/7), 7-5
Frances Tiafoe (USA) bt Julien Benneteau (FRA) 4-6, 6-3, 6-4, 6-2
Kyle Edmund (GBR x21) bt Bradley Klahn (USA) 6-4, 7-6 (7/0), 6-2
Novak Djokovic (SRB x12) bt Horacio Zeballos (ARG) 6-1, 6-2, 6-3
Nick Kyrgios (AUS x15) bt Robin Haase (NED) 6-3, 6-4, 7-5
Kei Nishikori (JPN x24) bt Bernard Tomic (AUS) 2-6, 6-3, 7-6 (9/7), 7-5
Ernests Gulbis (LAT) bt Damir Džumhur (BIH x27) 2-6, 6-4, 6-3, 1-6, 6-3
Juan Martín Del Potro (ARG x5) bt Feliciano Lopez (ESP) 6-4, 6-1, 6-2
Benoît Paire (FRA) bt Denis Shapovalov (CAN x26) 0-6, 6-2, 6-4, 7-6 (7/3)
Gilles Simon (FRA) bt Matteo Berrettini (ITA) 6-3, 7-6 (7/4), 6-2
Matthew Ebden (AUS) bt Stéphane Robert (FRA) 6-3, 7-6 (7/5), 4-6, 6-1
Jirí Veselý (CZE) bt Diego Schwartzman (ARG x14) 6-3, 6-4, 7-6 (7/3)
Fabio Fognini (ITA x19) bt Simone Bolelli (ITA) 6-3, 6-4, 6-1
Alex De Minaur (AUS) bt Pierre-Hugues Herbert (FRA) 6-2, 6-7 (8/10), 7-5, 6-3
Rafael Nadal (ESP x2) bt Mikhail Kukushkin (KAZ) 6-4, 6-3, 6-4
Suspended for darkness:
Taylor Fritz (USA) leads Alexander Zverev (GER x4) 4-6, 7-5, 7-6 (7/0)
Simona Halep (ROM x1) bt Zheng Saisai (CHN) 7-5, 6-0
Hsieh Su-Wei (TPE) bt Lara Arruabarrena (ESP) 6-3, 6-3
Dominika Cibulkova (SVK) bt Johanna Konta (GBR x22) 6-3, 6-4
Elise Mertens (BEL x15) bt Sachia Vickery (USA) 6-1, 6-3
Jelena Ostapenko (LAT x12) bt Kirsten Flipkens (BEL) 6-1, 6-3
Vitalia Diatchenko (RUS) bt Sofia Kenin (USA) 6-4, 6-1
Daria Gavrilova (AUS x26) bt Samantha Stosur (AUS) 6-4, 6-1
Aliaksandra Sasnovich (BLR) bt Taylor Townsend (USA) 6-0, 6-4
Alison Van Uytvanck (BEL) bt Garbiñe Muguruza (ESP x3) 5-7, 6-2, 6-1
Anett Kontaveit (EST x28) bt Jennifer Brady (USA) 6-2, 7-6 (7/4)
Ashleigh Barty (AUS x17) bt Eugenie Bouchard (CAN) 6-4, 7-5
Daria Kasatkina (RUS x14) bt Yulia Putintseva (KAZ) 6-2, 6-3
Angelique Kerber (GER x11) bt Claire Liu (USA) 3-6, 6-2, 6-4
Naomi Osaka (JPN x18) bt Katie Boulter (GBR) 6-3, 6-4
Carla Suárez Navarro (ESP x27) bt Sara Sorribes (ESP) 6-4, 6-1
Belinda Bencic (SUI) bt Alison Riske (USA) 1-6, 7-6 (12/10), 6-2
Barbora Strycova (CZE x23) bt Lesia Tsurenko (UKR) 6-1, 6-4
Katerina Siniakova (CZE) bt Ons Jabeur (TUN) 5-7, 6-4, 9-7