Top seed Zhang Shuai came through her opening outing but Eugenie Bouchard was knocked out early at the Japan Women's Open on Tuesday.

Last on court, Zhang was broken three times on her own serve but still saw off Magdalena Frech 7-5 6-3, giving her a welcome lift after losing in the first round at the US Open.

Bouchard, however, fell at the first hurdle, the Canadian going down in straight sets against home favourite Nao Hibino in Hiroshima.

Su-Wei Hsieh also appeared in danger of an early exit when she lost the opener against Polona Hercog, only for the second seed to rally for a 4-6 6-1 6-3 victory.

There was a scare for Wang Qiang too, the fourth seed battling back from a set down to beat Priscilla Hon 3-6 6-1 6-3.

Fellow seeds Zarina Diyas and Magda Linette also progressed, recording comfortable wins over Sara Sorribes Tormo and Johanna Larsson respectively.

Diyas - the defending champion who claimed her maiden WTA Tour title when the tournament was staged in Tokyo last year - dropped just three games in a one-sided match that lasted 67 minutes.

"I'm not thinking about defending a title, I'm just trying to enjoy to play every match and every game here. I'm feeling good. It was a really good game today. It was tough," Diyas told the WTA's website.