That year, Ai had better results in doubles than in singles. Partnering with Elena Dementieva, she reached the finals of her first tournament, Sydney, losing to Bryanne Stewart/Samantha Stosur. They reached the round of 16 at the Australian Open. She entered a few tournaments with Anastasia Myskina and Elena Likhovtseva, but with poor results. In Berlin, she played again with Daniela Hantuchová, reaching the semifinal, losing to Black and Huber. At the French, they lost to Birnerová and Vanc in the second round. They won their next tournament, in Birmingham over Daniilidou and Russel 6–2, 6–3. At Wimbledon, Hantuchová and Sugiyama reached the quarterfinal, losing to eventual champions Black and Huber. At the Canadian Open in Toronto, they lost the semifinal to eventual champions Grönefeld and Navratilova. At the US Open, they reached the third round, losing to Yan Zi and Zheng Jie. She tried three partners in the next tournaments, before returning to Daniela in Zurich, where they reached the finals (beating top seeds Lisa Raymond and Stosur en route), losing a close match to Black and Rennae Stubbs, 7–6, 6–7, 3–6. They finished the year ranked No. 5, failing to qualify for the year-end championships.