Bernet, seeded 3/4, found himself two games down against South Africa's Luhann Groenewald, who plays with an unorthodox double-handed style reminiscent of the former world No.2 Peter Marshall. 

However, Bernet - winner of the European Junior Open earlier this year - battled back to win 12-14, 5-11, 11-9, 11-8, 11-7. He later beat Colombia's Juan Irisarri in four games to claim his place in the last eight against Egyptian Yayhya Abouraya.

Boys' U19 top seed Mohamed Zakaria of Eygpt cruised through both his matches on Thursday to set up a quarter-final with USA's 9/16 seed Zane Patel.

England's Jonah Bryant is another European in the quarter-final line-up although he had to dig in to get past Egyptian Youssef Asheba, who battled back from two games down. Former champion Bryant then dispatched USA's Alexander Dartnell with ease. France's Melvil Scianimanico - European ranked No.3 - is also into the quarter-finals after beating Egypt's Yassin Shohdy. USA have three representatives in the last eight for the first time.

There is no European representation in the girls' U19 quarter-finals though after England's Amelie Haworth went down to USA's 5/8 seed Riya Navani in round three. Avery Park - the first American ever to be ranked No.1 on the ESF junior circuit - sadly had to withdraw from her third round match with Janna Galal.

Egypt's top seed Fayrouz Abouelkeir sailed through both her matches to set up a quarter-final against Sehveetrraa Kumar of Malaysia on Friday. At the opposite end of the draw, USA's second seed Caroline Fouts is also comfortably through and takes on Egypt's Noor Megahed (5/8) next.

The girls’ U17 went mainly to seeding, with Egypt’s Sohayla Hazem Farouk and Malaysia’s Doyce Lee Ye San, both [9/16] seeds, joining six of the top seeds in the quarters - including France's Lauren Baltayan, who is currently top of the European girls' U17 rankings.

In the boys’ U17 the top four seeds all won through, but all four 5/8 seeds failed to advance including Belgium's Maddox Moxham. France's Amir Khaled did progress to the quarters, though, and faces Egyptian top seed Youssef Salem on Friday morning.

There was a big upset in the boys’ U15 where Egyptian 17/32 seed Seif Belal El Shal beat Malaysia's second seed Jayden Oon before winning his last-16 match with India’s Subhash Choudhary to gatecrash the quarters. English 9/16 seed George Griffiths and unseeded Kuwaiti Abdullah Ali also advanced to the last eight.

There was also surprise in the girls' 15 last 16 as USA’s [9/16] Isabella Tang took out [3/4] seed Mariam Eissa in four games to join the other top seeds in the last eight. Savannah Moxham of Belgium is flying the flag for Europe in the quarter-finals. She faces USA's second seed Harleein Tan on Friday afternoon.

There were no real upsets in the boy's U13 draw as Malek Helmy and Omar Mohamed, both of Egypt, moved safely into the quarters. In the girls' U13s, 3/4 seed Niea Chew of Malaysia lost in four tight games to 9/16 Ethar Elhadidy but there were few surprises elsewhere.

Pakistani top seed Muhammad Harmas Ali Raja and second seed Hisshan Nair Tan remain on course for the boys' U11 final after coming through contrasting tests on Thursday. Tan, of Malaysia, had to recover from 2-1 down against Egypt's Hassan Khater, winning the last two games 12/10, 13/11.

The top two seeds from USA - Kaylee Li and Megha Ravichandran - both made it through comfortably to Friday's play in the girls' U11, with the other six quarter-final spots all taken up by Egypt.