Organizers apologized Monday for a ceremony involving female models provocatively revealing the letters "A" or "B" to determine the draw for the ATP's Next Gen Finals tennis tournament.
The ceremony on Sunday was supposed to highlight Milan's status in the fashion industry.
"The intention was to integrate Milan's rich heritage as one of the fashion capitals of the world," the ATP and sponsor Red Bull said in a statement. "However, our execution of the proceedings was in poor taste and unacceptable. We deeply regret this and will ensure that there is no repeat of anything like it in the future."
Earlier, two-time Grand Slam champion Amelie Mauresmo tweeted, "Disgrace," while Andy Murray's mother Judy added, "Awful."
Players were asked to select models who then revealed an "A" or a "B" to determine which group they will play in. One model pulled up her dress to reveal an "A" on her right thigh.
The Italian tennis federation declined comment, saying the ATP organized the draw ceremony.
The top seven 21-and-under players in the rankings plus one Italian wild-card entry qualified for the tournament, which starts Tuesday. The top-seeded players are Andrey Rublev and Karen Khachanov.
Top qualifier Alexander Zverev withdrew to focus on the main ATP finals next week in London.
Rublev, Canadian Denis Shapovalov, Chung Hyeon and Gianluigi Quinzi were drawn into Group A. Group B features Khachanov, Borna Coric, Jared Donaldson and Daniil Medvedev.
Writing for sport360.com, journalist Reem Abulleil, who was at the draw ceremony, wrote: "There was inappropriate dancing, gloves that were removed by a player's teeth, and many more cringe-worthy moments but I'll spare you the details.
"Most of the players looked visibly awkward, while some laughed their way through it. I personally felt deeply sad watching it all unfold."
The ceremony was sponsored by Red Bull and, in a joint statement, the drinks company and the ATP apologized for the offense which had been caused.
"The intention was to integrate Milan's rich heritage as one of the fashion capitals of the world," read the statement.
"However, our execution of the proceedings was in poor taste and unacceptable. We deeply regret this and will ensure that there is no repeat of anything like it in the future."