Vasek Pospisil’s anger boiled over in a foul-mouthed rant referencing ATP Tour chairman Andrea Gaudenzi Wednesday as the Canadian went down in three sets in the first round of the Miami Open.

American qualifier Mackenzie McDonald advanced with a 6-3, 4-6, 6-3 victory over Pospisil, who swatted a ball out of court, smashed a racket and incurred a verbal abuse point penalty on set point of the opening set – a display that had him later offering an apology on Twitter.

Asked during a changeover by umpire Arnaud Gabas what the problem was, 67th-ranked Pospisil unleashed a tirade focused on Gaudenzi.

“For an hour-and-a-half yesterday, chair of the ATP... screaming at me in a player meeting for trying to unite the players,” Pospisil said. “For an hour and a half. The leader of the ATP. Get him out here. Why am I supporting this?”

Pospisil was a key figure along with world No 1 Novak Djokovic in launching the Professional Tennis Players’ Association last year, a body they said they hope will give players a greater voice in the sport.

The idea has divided opinion, with such stars as Roger Federer and Rafael Nadal saying they don’t think the time is right for such a move.

“I want to sincerely apologise for my behavior on the court in Miami earlier today,” Pospisil later tweeted. “I disrespected the game I love and for that I am truly sorry. By way of explanation, I felt deeply unnerved during a meeting between players and ATP executives last night, and I underestimated the toll those emotions took on me until I stepped onto the court today.

“Again, I am sorry for my on-court behavior and the language I used.”

Pospisil pulled himself together to win the second set, but McDonald, ranked 120th in the world, bounced back to seal the match and set up a second-round meeting with 18th-seeded American John Isner.

Isner is another player who has called for an economic overhaul in the sport, branding the ATP a “broken system” in February after it was revealed the pandemic-hit Miami Open – an elite Masters 1000 event for the ATP – had cut prize money for singles winners from $1.35 million in 2019 to just over $300,000 this year.

Results

Men, first round

Lu Yen-Hsun (TPE) bt Sam Querrey (USA) 6-3, 6-4

Alexei Popyrin (AUS) bt Feliciano Lopez (ESP) 6-4, 7-6 (7/4)

Frances Tiafoe (USA) bt Stefano Travaglia (ITA) 5-7, 6-4, 6-2

Ernesto Escobedo (USA) bt Paolo Lorenzi (ITA) 6-3, 6-2

Pierre-Hugues Herbert (FRA) bt Pedro Sousa (POR) 6-1, 6-3

Mackenzie McDonald (USA) bt Vasek Pospisil (CAN) 6-3, 4-6, 6-3

Ricardas Berankis (LTU) bt Federico Gaio (ITA) 7-6 (7/4), 6-2

Lloyd Harris (RSA) bt Emilio Nava (USA) 6-4, 7-6 (9/7)

Emil Ruusuvuori (FIN) bt Carlos Alcaraz (ESP) 6-4, 2-6, 7-5

Mikael Ymer (SWE) bt Alejandro Tabilo (CHI) 6-3, 6-1

Hugo Gaston (FRA) bt Dominik Koepfer (GER) 6-1, 6-4

Yannick Hanfmann (GER) bt Steve Johnson (USA) 7-5, 6-2

Cameron Norrie (GBR) bt Yoshihito Nishioka (JPN) 6-1, 3-6, 7-5

Marcos Giron (USA) bt Tommy Paul (USA) 7-6 (7/5), 6-4

Laslo Djere (SRB) bt Jiri Vesely (CZE) 6-3, 5-7, 6-1

James Duckworth (AUS) bt Mischa Zverev (GER) 6-2, 4-6, 6-4

Women, first round

Kristina Kucova (SVK) bt Hailey Baptiste (USA) 6-4, 2-6, 7-5

Jelena Ostapenko (LAT) bt Wang Xiyu (CHN) 6-4, 6-7 (4/7), 6-1

Renata Zarazua (MEX) bt Nao Hibino (JPN) 6-4, 4-6, 6-1

Wang Qiang (CHN) bt Aliona Bolsova (ESP) 6-1, 3-6, 6-3

Danielle Collins (USA) bt Kristina Mladenovic (FRA) 6-3, 6-3

Tsvetana Pironkova (BUL) bt Marta Kostyuk (UKR) 7-6 (7/4), 3-6, 6-3

Caroline Garcia (FRA) bt Mihaela Buzarnescu (ROM) 6-1, 6-2

Anastasija Sevastova (LAT) bt Olga Danilovic (SRB) 6-1, 3-6, 7-6 (7/3)

Ana Konjuh (CRO) bt Katerina Siniaková (CZE) 7-6 (7/3), 7-5

Alize Cornet (FRA) bt Svetlana Kuznetsova (RUS) 2-6, 6-2, 6-1

Tereza Martincova (CZE) bt Yaroslava Shvedova (KAZ) 6-4, 6-2

Sloane Stephens (USA) bt Océane Dodin (FRA) 6-7 (6/8), 6-4, 6-2

Anna Kalinskaya (RUS) bt Irina Begu (ROM) 6-4, 7-6 (7/5)

Sara Sorribes (ESP) bt Bernarda Pera (USA) 6-2, 2-6, 7-5

Andrea Petkovic (GER) bt Zhang Shuai (CHN) 7-5, 6-1

Zheng Saisai (CHN) bt Fiona Ferro (FRA) 2-6, 6-4, 6-3

Storm Sanders (AUS) bt Elisabetta Cocciaretto (ITA) 6-1, 5-7, 6-1

Liudmila Samsonova (RUS) bt Camila Giorgi (ITA) 6-2, 6-4

Katie Boulter (GBR) bt Kristyna Pliskova (CZE) 4-6, 6-3, 6-3

Nina Stojanovic (SRB) bt Heather Watson (GBR) 6-4, 6-1