Gerard, the eighth seed, was beaten 6-4, 2-6, 6-1 by his Japanese opponent at the Blacktown Tennis Centre.

Sanada's reward for stunning the 29-year-old Belgian is a meeting with third seed Stephane Houdet, of France.

Houdet booked his place in the last 16 courtesy of a battling 6-2, 6-7, 7-5 win over unseeded Chinese player Chao Du.

Paralympic champion Gordon Reid of Britain also progressed as he thrashed Yoshinobu Fujimoto of Japan 6-0, 6-1.

Nicolas Peifer, of France, a 6-1, 6-4 winner over South Africa's Eliphas Maripa, awaits Reid in round two.

Alfie Hewett, the Paralympic silver medallist who beat compatriot Reid in the final of last year's Wheelchair Tennis Masters, is through after he overcame Australia's Ben Weekes 6-2, 7-5.

Hewett will face sixth seed Stefan Olsson in the second round after the Swede swept aside Daisuke Arai of Japan 6-0, 6-1.

Top seed Gustavo Fernandez of Argentina also had little trouble in reaching the last 16 as he comfortably beat Japan's Kouhei Suzuki 6-1, 6-0.

In the women's tournament, Paralympic bronze medallist and top seed Yui Kamiji of Japan dropped just a single game on her way to ousting Hui Min Huang of China 6-1, 6-0.

Britain's Lucy Shuker, the sixth seed, will be Kamiji's opponent as she beat Japanese player Manami Tanaka 6-0, 6-3.

The tournament in the 2000 Paralympic Games host city is due to continue tomorrow, with action in the quad singles among the highlights.