The 22-year-old was down 2-0 in the first set of a second-round defeat against Karolina Muchova of the Czech Republic on Tuesday when she approached the umpire, then briefly took refuge behind his chair.
The WTA said it would ban the man involved after he had approached Raducanu in a public area on Monday where he exhibited "fixated behaviour" before taking a courtside seat during the first few rows for her match on Tuesday.
He was escorted away with Muchova rushing to comfort her before play resumed.
Raducanu, reflecting on the incident in a post to her Instagram feed, said Wednesday: "Thank you for the messages of support.
"Difficult experience yesterday but I'll be okay and proud of how I came back and competed despite what happened at the start of the match.
"Thank you to Karolina for being a great sport and best of luck to her for the rest of the tournament."