Foreign and domestic fans clad in the colors of the 20 teams playing in the Rugby World Cup flooded into the stadium that hosted the tournament's opening match between Japan and Russia in Tokyo on Friday.

Fans stopped for selfies, held aloft banners and queued up at stalls selling beer, food and official goods as volunteers and organizers scrambled to ensure a team effort would deliver a smooth opening to the sport's showpiece event.

"We are excited that Japan will put on a spectacular opening ceremony. Japan is a very good team, we hope they will win by scoring many tries," said 65-year-old Wales native Isobel Smith at Tokyo Stadium (Ajinomoto Stadium).

She said they plan to watch four games, including two played by Wales, in her nearly three-week stay with her husband Anthony, 69.

"Sometimes the Japanese people are shy but they have been very helpful, polite and disciplined, just like the Japanese team," she said.

"While some European cities nowadays have issues with security, it is good that I feel safe," she said, adding that she is enjoying the food and traveling in between games, such as to Kanazawa on the Sea of Japan coast.

World Cup organizers have predicted more than 400,000 overseas visitors will come for the tournament, bringing in a 437.2 billion yen ($4 billion) economic windfall from match tickets and the sale of goods and services.

Helen Tavener, 63, from England said she is taking the opportunity to watch eight matches during her 28-day stay in Japan, while sightseeing in Sapporo in the country's northernmost main island of Hokkaido and Hiroshima in the west.

"It's been wonderful here. The people are friendly and very helpful," Tavener said, waiting for the match to start with her husband Stephen, 65.

"The tournament is very competitive with many teams having the chance to win," she said, naming England, South Africa, Ireland and New Zealand as her tips for the cup.

In the Shimbashi district of Tokyo, people watching the game on TV in a packed English pub cheered uproariously as Japan snagged a convincing 30-10 victory against Russia.

"This might be the first time that I watched a rugby match so closely," said Toru Inage, 37, after watching the game with his coworker.

Naming No. 8 Kazuki Himeno as the player of the game, Inage said, "I found (rugby) is a sport with a sense of speed, and the sound of their bodies slamming into each other was really powerful. It was super fun."

Akira Yamaguchi, who stopped by after work, said that after seeing the Brave Blossoms perform, he thinks they could be the dark horse of the tournament.

"This win gave them a lot of momentum. I think they can reach the knockout stage," he said.

Japan have never reached a quarterfinal in eight World Cup campaigns and doing so would be a historic achievement for the hosts.

Yamaguchi, 40, added that he anticipates another strong performance from full back Kotaro Matsushima, who scored a hat-trick of tries on Friday, in Japan's next match against No. 1-ranked Ireland.