The top half of the Japan Women's Open draw opened up even further on Wednesday, as fifth seed Johanna Larsson was eliminated.

Belgium's Yanina Wickmayer defeated Larsson 7-5 6-3, while seventh seed Ajla Tomljanovic had to survive an early scare to reach the last-eight, after overcoming local hope Kimiko Date-Krumm 7-6 (7-5) 6-3.

If Tomljanovic had lost, Madison Brengle would have been the only seed remaining in the top half of the draw at the WTA International event in Tokyo after top-ranked Carla Suarez Navarro lost her first-round match to Kateryna Bondarenko.

Larsson struggled to make an impact on Wickmayer's serve, with the Swede winning just 18 per cent of first-serve points she faced and converting only two of seven break-point opportunities.

Meanwhile, Wickmayer broke Larsson at key points in both sets.

After Larsson surged late in the first set, Wickmayer broke the former for a second time to claim the set.

Larsson broke Wickmayer in the opening game of the second but the 25-year-old responded immediately to level at 1-1 and claimed her fourth break of the contest in the penultimate game, as she went on to triumph in one hour, 41 minutes.

Date-Krumm started brilliantly against Tomjlanovic, winning the first three games, but the Croatian world number 61 responded by winning the next three.

Tomjlanovic would eventually claim the first set in a tie-break after 67 minutes before taking control of the match with four straight games to begin the second set.

Brengle cruised past Date-Krumm's compatriot Nao Hibino 6-1 6-2 and the American third seed will face Tomjlanovic in the quarter-finals.

Meanwhile Brengle's compatriot - and the sixth seed - Christina McHale trumped qualifier Risa Ozaki 6-1 7-5.