The world's leading players from more than 30 countries are competing in the Hi-Tec World Squash Championships – Manchester 2008, the first ever joint staging of the Men's World Open and Women's World Open in the UK.
"My best result by far," was how Grant described his sensational five-game upset over the Frenchman who was runner-up in the last two World Opens. The left-hander from London saved three game balls in the third game before taking a 2/1 lead in the match.
But Gaultier, the world No2 from Aix-en-Provence, struck back in the fourth to level the match for the loss of just a single point. It was nip and tuck throughout the decider before the match favourite reached match-ball at 10-8. 
But Grant saved this, and two further match-balls, before clinching his career-best result by beating Gaultier 9-11, 12-10, 14-12, 1-11, 13-11 after 98 minutes.
"This is a massive step for me - definitely my best result by far," said the 28-year-old 14th seed. "His record here is unbelievable.
"He came out firing in the fourth - and, before I knew it, it was all over. But he's two in the world, so he must have felt the pressure towards the end," added the Leeds-based England international after his first ever win over the Frenchman.
It was a 'very, very upset' Gaultier that spoke to the press afterwards. "I lost my head. He played better - he's a much better player than me, that's it. Good luck to him."
When asked if it was true that the pair were good friends, the Frenchman replied: "Yes, but there are no friends on court."
Hopes of a completely unexpected all-English quarter-final were dashed in the final match of the day when Egypt's seventh seed Karim Darwish recovered from a game down to beat Gloucestershire's unseeded Alister Walker, based in Leeds, 9-11, 11-8, 11-5, 11-8.
Englishman James Willstrop will be after revenge when he faces Australia's former world champion David Palmer in the quarter-finals.
Palmer, a two-time winner of the World Open title, was extended for 83 minutes by unseeded Englishman Daryl Selby before beating the world No36 from Essex 11-5, 11-13, 11-3, 12-10.
"It's pretty hard to believe he's 36 in the world," sighed Palmer afterwards. "It seems that all the young guys in the world have stepped up. It's been a great tournament for him."
In a re-match of the British Open final in May in Liverpool, where Palmer saved match balls in the final to take the title for a fourth time, the 32-year-old from Lithgow in New South Wales will face England's James Willstrop
The Yorkshireman had to play one of the rallies of his life to save a game-ball in the second before going on to stop Italian number one Davide Bianchetti 11-7, 13-11, 11-8 in 48 minutes.
"It's always good to get people off as quickly as possible in a tournament like this where there are so many matches," Willstrop, the England number one, explained. "It's extremely important not to waste energy."
When reminded that Palmer would be his next opponent, Willstrop said: "They don't come a lot bigger. It's never going to be easy, but I do urge the crowd to get behind me - it really does
England's Nick Matthew prevented it from being an all-Egyptian day in the four men's third round matches on the all-glass show court when he beat Dutchman Laurens Jan Anjema 11-7, 11-6, 11-13, 11-4 in exactly one hour.
In only his third event following a nine-month layoff after shoulder surgery, the 28-year-old from Sheffield showed the form which won him the British Open title two years ago. "I felt pretty good - I feel I've been pretty well in the tournament so far, but not yet in a whole match.
"Physically, I'm better than I've ever been - because while I was recovering from the shoulder, fitness was all I could work on!"
In Friday's quarter-finals, Matthew will face Ramy Ashour, the fourth seed from Egypt who put paid to an all-English last eight clash by beating Londoner Peter Barker, the 12th seed, 11-8, 11-13, 11-8, 11-6.
"I was up for it today - all the work I have put in in the last couple of months has paid off," said the exuberant 21-year-old afterwards. "But six days before the championships, I pulled a hamstring, and didn't play at all. It actually gave me a bit of a break."
Later in the day, Mohamed El Shorbagy became the first qualifier for 22 years to reach the men's quarter-finals when he beat Hisham Mohd Ashour 11-4, 6-11, 11-8, 10-12, 13-11.
The 17-year-old Egyptian became event's giant-killer after battling through to the second round - then beating experienced Frenchman Thierry Lincou to reach the last sixteen.
"I've played five days in a row now - and tomorrow I get a day off. Now I will chill out," said the teenager.
Official site:
Men's 3rd round:
[1] Amr Shabana (EGY) bt [9] Wael El Hindi (EGY) 11-9, 2-11, 11-4, 12-14, 11-6
[Q] Mohamed El Shorbagy (EGY) bt Hisham Mohd Ashour (EGY) 11-4, 6-11, 11-8, 10-12, 13-11
[4] Ramy Ashour (EGY) bt [12] Peter Barker (ENG) 11-8, 11-13, 11-8, 11-6
[8] Nick Matthew (ENG) bt [15] Laurens Jan Anjema (NED) 11-7, 11-6, 11-13, 11-4
[5] David Palmer (AUS) bt Daryl Selby (ENG) 11-5, 11-13, 11-3, 12-10
[3] James Willstrop (ENG) bt Davide Bianchetti (ITA) 11-7, 13-11, 11-8
[7] Karim Darwish (EGY) bt Alister Walker (ENG) 9-11, 11-8, 11-5, 11-8
[14] Adrian Grant (ENG) bt [2] Gregory Gaultier (FRA) 9-11, 12-10, 14-12, 1-11, 13-11
Issued by iSPORTmedia

Hi-Tec World Open Squash Championships, Manchester, England
England's Adrian Grant upset the form book in dramatic stylein the third round of the Hi-Tec World Open Squash Championships after saving three match balls to beat France's No2 seed Gregory Gaultier to reach the men's quarter-finals at the National Squash Centre at Sportcity in Manchester.