Nour El Sherbini, the top seed and British Open champion in 2016, rallied superbly from 1-2 down to defeat home ninth seed Alison Waters.

Waters took advantage of a bad start by her top-ranked opponent by El Sherbini grew in confidence as her opponent struggled with dizziness in the fourth set.

The Egyptian eventually triumphed 6-11, 11-4, 11-13, 11-7, 11-5 in a 58 minute dual.

“I don’t know what was happening in the third,” said El Sherbini.

“She came back strongly and was playing so good but I was glad I had my coach with me and he told me to keep going.

“I’m glad I came back in the fourth and fifth and played good."

Reigning champion Laura Massaro breezed into the semi-finals at Egypt's expense, however.

Massaro, seeded seventh, is yet to drop a game in the entire tournament and emphatically beat third-seed Nour El Tayeb 11-9, 11-9, 11-6.

It avenged a loss to the same opponent at the US Open earlier this year.

France's sixth seed Camille Serme was forced to dig deep before a 72 minute 16-14, 7-11, 7-11, 11-9, 11-6 win over Wales' Tesni Evans elsewhere today.

Top seed Mohamed ElShorbagy won 11-6, 6-11, 12-10, 11-7 against Paul Coll of New Zealand in the men's singles draw.

Third-seeded Frenchman Gregory Gaultier also thrashed Germany's Simon Rösner 11-7, 11-6, 11-5.

The biggest shock of the day came late-on, however, as German qualifier Raphael Kandra continued his giant-killing run by beating Egypt's Marwan ElShorbagy 11-7, 11-13, 6-11, 13-11, 11-6.

It followed his win over England's Nick Matthew in the previous round.