Seven youths, including the 14-year-old "ringleader", had already admitted raping the 32-year-old woman in September last year, John Bevan QC, prosecuting, told the Old Bailey jury.
A boy aged 15, alleged to be the eighth member of the gang, who cannot be identified for legal reasons, denies three charges of rape, indecent assault and robbery.
The woman, who cannot be named, was kicked, punched, and subjected to a multiple rape ordeal and other "sexual indignities" after going for a midnight stroll from her hotel in the King's Cross area of London, Mr Bevan said.
"It may be she was naive. On the other hand, it may be that she simply thought London was a safe place for a woman alone. She was sadly mistaken. She was approached and, as she thought, idly chatted to by a group of eight people she regarded as children.
"Once they took her to where they could safely attack her, she was frogmarched down Regent's Canal and, after her clothing had been torn off her, she was violently and repeatedly raped by each one in turn.
"She was then thrown into the canal. She survived. Perhaps it is a tribute to her toughness and good sense that she did, once she realised that resistance was hopeless and indeed dangerous."
Mr Bevan said: "The behaviour of these youths, acting in a pack as they were, defies rational understanding. The oldest was 17, while the rest were 16 or less and three of them, including this defendant, were 14.
Mr Bevan said the youths asked her if she wanted to go to a party, but she told them in her halting English that it was not a good idea. Then they dragged her along a towpath.She was stripped, hit and kicked in the face and thrown to the ground "and pinioned by her arms and legs".
Mr Bevan said the woman was "raped repeatedly" and compelled to perform other acts on some of the gang. One black youth who made her perform a sex act "threatened to kill her if she bit him in the process", Mr Bevan said.
He said the offence was "overtly racist in nature", as there were repeated references to "the white bitch".
Thevictim, aged 33 and living in Vienna, said that as they dragged her along the canal bank they held her mouth shut.
Mr Bevan asked her what she thought they wanted. "I thought they were going to rob me," she replied. "They stopped and the biggest one said 'Now the party's beginning'."
The trial was adjourned until today.