“But I’m proud of myself how I fought back from being down a double break in both sets, and then I just stuck with it and I’m happy to be through.
“I really felt at home here again. I’m really grateful for everyone who came to support me today. That’s what helped me get through it as well.”
Xu is one of four British players through to the quarter-finals and she will take on sixth seed Harmony Tan.
France’s Tan is the lone seed left in the draw after her 6-3, 7-5 win over Sweden’s Kajsa Rinaldo Persson.
There was more British success in the singles as Lily Miyazaki upset top seed Jessika Ponchet in a convincing 6-2, 6-4 win, while Ella McDonald defeated Ivana Sebestova in straight sets 6-3, 7-5.
Sixteen-year-old Mika Stojsavljevic triumphed 6-4, 6-4 in an all-British clash with Amarni Banks.
Czechia’s Lucie Havlickova is also through to the quarter-finals of the singles after a straight-sets win over fourth seed Kathinka von Deichmann.
Fifth seed Raluca Serban of Cyprus also bowed out in straight sets to Belgium’s Jana Otzipka.
Estonia’s Elena Malygina completes the quarter-final line-up after a straight-sets win over Katarina Kuzmova.
