Home player Alfie Hewett was the most notable casualty in the men's singles draw on day two of the British Open Wheelchair Tennis Championships in Nottingham.
The fourth seed lost 4-6, 6-3, 6-2 to the Netherlands' Tom Egberink at the International Tennis Federation Super Series event at Nottingham Tennis Centre.
He was joined in suffering second-round elimination by sixth-seeded Swede Stefan Olsson, who was beaten 6-2, 3-6, 6-3 by Japan's Takuya Miki.
All the other seeded players went through to the quarter-finals, including top-ranked Gustavo Fernández of Argentina and second-ranked Shingo Kunieda of Japan.
Fernández defeated Japan’s Takashi Sanada 6-2, 6-4, while Kunieda overcame Britain's Dermot Bailey 6-3, 6-0.
In the women's singles, eighth-seeded Briton Lucy Shuker was among the players to exit at the second-round stage after losing 6-3, 6-3 to the United States' Dana Mathewson.
Top seed Diede de Groot of the Netherlands beat Colombia's Angelica Bernal 6-1, 6-1, while second-seeded compatriot Aniek van Koot defeated France's Charlotte Famin 6-3, 6-3 to set up a last-eight encounter with Mathewson.
The only two seeded players to crash out of the quad singles draw were sixth-ranked Robert Shaw of Canada and eighth-ranked Bryan Barten of the US.
Shaw was forced to retire from his last-16 match against Japan's Shota Kawano when trailing 2-0 in the deciding set.
Kawano will now face second-seeded compatriot Koji Sugeno in the quarter-finals after he overcame Chinese Taipei's Huang Chu-yin 6-0, 6-1.
Barten, meanwhile, was beaten 6-4, 6-4 by the Netherlands' Niels Vink.
Top seed Andy Lapthorne of Britain eased into the last eight by defeating Japan’s Mitsuteru Moroishi 6-2, 6-4.