The man, named only as Theo, a 31-year-old from eastern Germany, is known to have sent gifts to Huber, 18, and to have written her love letters.
He is also reported to have been arrested after getting into her hotel during the Citizens Cup tournament in Hamburg eight weeks ago, in which Monica Seles was stabbed.
On Tuesday, Huber's compatriot and the top seed, Steffi Graf, was upset when Kurt zum Felde, 29, also a German, shouted at her while she was on court and blamed her for the stabbing of Seles.
Yesterday 'Theo' watched Huber's match on Court Two from a railing some 20 yards away. He made no attempt to make himself known to her. Dressed in a blue sweatshirt and jeans, he applauded as she won her match convincingly in straight sets.
Huber had warned the authorities about 'Theo', who has followed her for several years, and was at both the Australian Open and the French Open.
Scotland Yard said police were only informed about the possibility of his presence by the media. Detectives watched him during the match and afterwards he was questioned by journalists as he tried to leave.
He said in German: 'Are you sick? I don't want to talk about it. Leave me alone, get away.'
He then left the ground by a nearby exit and bolted into a tent across the road. Inside, he could be seen talking to police, who were quickly on the scene and asked to be left alone.
The police led him outside and handed him over to the tournament organisers, who smuggled him away in a taxi.
A police spokesman said:
'She (Huber) has expressed concern about him and after the Seles attack we obviously have to take things very seriously, but no action was taken as he did not commit any crime.'Reuse content