A man displaying "fixated behaviour" towards Emma Raducanu was thrown out of the Dubai Duty Free Tennis Championships, the WTA has said.
Raducanu was seen to have broken down in tears early in her second round defeat to Karolína Muchová.
After going down 2-0 in the opening set of their second round, the 22-year-old British player approached umpire Miriam Bley.
Raducanu was clearly distressed as she sobbed while explaining something to Bley, who immediately looked off court and jumped onto her radio to relay a message.
"It doesn't look good for Raducanu. This is very, very concerning," a commentator said.
"You never want to see a player in tears on court; this is meant to be a fun game."
The WTA later released a statement saying a man had been removed from the tournament grounds and will be banned from all future WTA events.
"On Monday, February 17, Emma Raducanu was approached in a public area by a man who exhibited fixated behaviour," the WTA said in a statement.
"This same individual was identified in the first few rows during Emma's match on Tuesday at the Dubai Duty Free Tennis Championships and subsequently ejected.
"He will be banned from all WTA events pending a threat assessment."
The 2021 US Open winner walked behind the umpire's chair while Muchová sought an explanation from Bley, before walking over to comfort her opponent.
Raducanu wiped her face with her towel and took a few deep breaths to compose herself before carrying on with the match, the start of which was delayed by rain.
Raducanu fell behind 4-0 in the first set before coming back to force a tie-break.
Coming off a win over world number 29 Maria Sakkari, Raducanu went down to 14th-seeded Muchová 7-6(8/6), 6-4.
The WTA said that player safety is its "top priority".
"Player safety is our top priority, and tournaments are advised on security best practices for international sporting events," the statement read.
"The WTA is actively working with Emma and her team to ensure her well-being and provide any necessary support.
"We remain committed to collaborating with tournaments and their security teams worldwide to maintain a safe environment for all players."