The New York-based 25-year-old beat experienced New Zealander Kashif Shuja 11-5, 11-8, 12-10 in 46 minutes to set up a second round meeting with second seed Gregory Gaultier, the new world number one from France.
"I was lucky to get in after Borja's withdrawal," explained Illingworth. "I came to fulfil my seeding - that was my goal. Anything else is a bonus."
Since graduating from Yale University in 2006, Illingworth has become the highest-ranked US player of all-time. "I shot up the rankings pretty quickly to around 50, and have been climbing steadily since then.
"I still feel I'm improving - and am now looking forward to playing Greg tomorrow on the all-glass court at Green Island. I've got nothing to lose - I'm just going to enjoy it."
Cheered on by a packed partisan crowd at the Salmiya Club, local wildcard player Abdullah Almezayen played the game of his life - and was three points away from a stunning upset against Egypt's 24th seed Omar Mosaad.
Twice the experienced 21-year-old from Cairo led in his first appearance in the event - and twice Almezayen, ranked 99 in the world, fought back to draw level as his exuberant fans revelled in the prospect of a historic breakthrough.
And in the decider, the local hero came back in a single hand from 0-5 down to 8-5 up. But Mosaad was in no mood to pander to the crowd: the world No25 raised his game and grabbed the next six points in succession to claim a notable 11-9, 10-12, 11-6, 9-11, 11-8 victory after 62 minutes.
"He's a good player - much more experienced than me," said the popular Kuwaiti left-hander. "And that was clear in the last few points - perhaps in the future I will be able to deal with those situations better.
"But overall I am very happy with today. This event has been great for squash in Kuwait - and it has also helped me get more personal sponsorship which will allow me to travel to more events on the world tour."
Whilst Omar Mosaad must have felt a million miles from home with the crowd willing his opponent to win, on an adjacent court fellow Cairo compatriot Omar Abdel Aziz was revelling in the support the locals gave him in his 11-5, 11-6, 15-13 upset over Miguel Angel Rodriguez, the 23rd seed from Colombia.
"For me, playing here provided the same atmosphere as in Egypt - people supporting me just like at home," said Aziz, the 26-year-old world No44. "I lost to Miguel in five games two weeks ago in Hong Kong - I started more consistently this time, going for my shots more. I am so happy to win."
Frenchman Renan Lavigne was delighted to provide the second upset of the day - on his 35th birthday! The world No38 from Marseille reproduced the same skills that took him to a career-high No17 five years ago to beat Canada's 30th seed Shahier Razik 11-9, 9-11, 11-5, 11-3 in 71 minutes.
"I lost the last two times we played - so I had double reason to celebrate," said the birthday boy afterwards. "I was pretty up for it - moving well and in good form - and it all worked out well."
2004 champion Thierry Lincou eased into the second round aftera convincing11-5, 11-7, 11-3 victory in 32 minutes over Pakistan qualifier Yasir Butt.
"I was not expecting an easy match," said the No8 seed from France¸ who made his debut in the 1998 championship after attempting to qualify for the first time the year before. "But you never know - the first round is often tricky.
"I felt pretty good coming into this tournament - I was up for it," said the 33-year-old former world number one. "He really surprised me at the beginning of each game - but I was able to react quickly and he then began to lose patience. And I was getting better - you do when you're in front."
English team-mates Peter Barker and James Willstrop also survived testing first round encounters. Barker, the No7 seed from London, faced qualifier Nicolas Mueller a rising squash star from Switzerland.
"He was probably one of the toughest first round opponents, so I was pleased to get it in three," said the 26-year-old left-hander after his confidence boosting 11-7, 11-2, 12-10 victory in 37 minutes. 
"It's been a tough month - I haven't been enjoying my squash too much recently. I got bogged down with some disappointing results, rather than concentrating on just enjoying playing.
"So I'm trying to play with a smile on my face again - and it seems to be paying off!"
Willstrop, a former world number two who is fighting back to the top of his game after ankle surgery earlier in the year, beat English qualifier Robbie Temple 13-11, 11-7, 11-0.
"He's improved a lot since I last played him," said the Yorkshireman of his left-handed opponent from Gloucestershire. "He played at a good pace and I had to move quickly and be sharp.
"I've got a hard draw and it's such a long tournament - I'm really keen to take each game as it comes. But it's such an exciting event, so you want to produce."
Indian number one Saurav Ghosal suffered the indignity of losing the first game without scoring a point - but refocused and battled back to beat French qualifier Mathieu Castagnet 0-11, 11-6, 11-8, 11-5 after 56 minutes.
"It was just weird," explained the 29th seed, from Chennai, afterwards. "He played really well - but I was in the rallies, but everything was wrong, even my body language.
"Malcolm (Willstrop) told me to try and at least look the part when he spoke to me after the first game," added the 23-year-old, now in the second round for the first time.
"It was hard - but I'm really pleased to win. It can only get better. It surely can't be worse than 11-0!"
A match which took 85 minutes of playing time - yet also featured a two-hour 'blood injury' break while Davide Bianchetti was taken to a local hospital - saw the Italian ultimately prevail 15-13, 11-6, 6-11, 11-2 over French qualifier Yann Perrin in the final match of the day at the Salmiya Club.
"Yann's racket caught me on the chin, and I had three stitches to stop the bleeding," explained the 32-year-old from Brescia on his return from hospital. "That wasn't as painful as the anti-tetanus injection in my backside - which seems to be restricting my movement."
Frenchman Gregory Gaultier celebrated his first day as world number one with a convincing straight games victory over Scot Alan Clyne on an all-glass squash court at the Green Island Resort.
The final four matches of the day were played in the spectacular open-air Green Island setting after all earlier matches were played at the Salmiya Club.
Gaultier, seeded to reach the final for the third time in four years, was in commanding form as he despatched Clyne 11-2, 11-5, 11-7 in just 27 minutes.
"It was a good first round match - I was really focussed and well-prepared," said the 26-year-old from Aix-en-Provence afterwards. "I knew it was his first time in the World Open and I was confident I would get through.
"But he gave me a good run, so I'm really pleased to have won 3/0."
1st round:
[1] Karim Darwish (EGY) bt Mansoor Zaman (PAK) 17-15, 11-4, 11-7 (30m)
[29] Saurav Ghosal (IND) bt [Q] Mathieu Castagnet (FRA) 0-11, 11-6, 11-8, 11-5 (56m)
[11] James Willstrop (ENG) bt [Q] Robbie Temple (ENG) 13-11, 11-7, 11-0 (35m)
[28] Jonathan Kemp (ENG) bt Arturo Salazar (MEX) 11-7, 11-4, 11-5 (25m)
[8] Thierry Lincou (FRA) bt [Q] Yasir Butt (PAK) 11-5, 11-7, 11-3 (32m)
[18] Stewart Boswell (AUS) bt [Q] Scott Arnold (AUS) 11-8, 12-10, 11-6 (39m)
[15] Alister Walker (ENG) bt Mark Krajcsak (HUN) 11-6, 11-6, 6-11, 11-5 (49m)
Renan Lavigne (FRA) bt [30] Shahier Razik (CAN) 11-9, 9-11, 11-5, 11-3 (71m)
[4] Amr Shabana (EGY) bt [Q] Shaun le Roux (ENG) 11-6, 11-5, 11-6 (32m)
[24] Omar Mosaad (EGY) bt Abdullah Almezayen (KUW) 11-9, 10-12, 11-6, 9-11, 11-8 (62m)
[12] Mohd Azlan Iskandar (MAS) bt Aaron Frankcomb (AUS) 11-6, 11-4, 11-2 (39m)
[22] Daryl Selby (ENG) bt [Q] Stephen Coppinger (RSA) 11-8, 11-6, 11-6 (38m)
[6] David Palmer (AUS) bt [Q] Julien Balbo (FRA) 11-5, 11-4, 11-6 (39m)
[25] Tarek Momen (EGY) bt Ben Ford (ENG) 11-9, 11-3, 11-6 (22m)
[9] Wael El Hindi (EGY) bt Stephane Galifi (ITA) 9-11, 11-8, 11-3, 9-11, 11-6 (85m)
Amr Swelim (ITA) bt [26] Joey Barrington (ENG) 11-8, 12-10, 11-9 (53m)
[21] Hisham Mohd Ashour (EGY) bt Chris Simpson (ENG) 6-11, 10-12, 11-6, 11-8, 11-5 (54m)
[10] Adrian Grant (ENG) bt Chris Ryder (ENG) 11-7, 11-6, 11-6 (36m)
[19] Olli Tuominen (FIN) bt [Q] Martin Knight (NZL) 11-6, 11-7, 11-9 (40m)
[7] Peter Barker (ENG) bt [Q] Nicolas Mueller (SUI) 11-7, 11-2, 12-10 (37m)
[17] Aamir Atlas Khan (PAK) bt Simon Rosner (GER) 11-9, 11-9, 11-5 (34m)
[14] Laurens Jan Anjema (NED) bt [Q] Rasmus Nielsen (DEN) 15-13, 11-6, 11-5 (34m)
Omar Abdel Aziz (EGY) bt [23] Miguel Angel Rodriguez (COL) 11-5, 11-6, 15-13 (57m)
[3] Ramy Ashour (EGY) bt Jorge Isaac Baltazar Ferreira (MEX) 13-11, 0-0 ret. (11m)
[20] Cameron Pilley (AUS) bt [Q] Joe Lee (ENG) 11-6, 11-4, 12-10 (39m)
[16] Mohamed El Shorbagy (EGY) bt [Q] Mohd Nafiizwan Adnan (MAS) 11-7, 11-5, 11-3 (25m)
[27] Davide Bianchetti (ITA) bt [Q] Yann Perrin (FRA) 15-13, 11-6, 6-11, 11-2 (85m)
[5] Nick Matthew (ENG) bt [Q] John Rooney (IRL) 11-6 ret. (12m)
[31] Tom Richards (ENG) bt [Q] Arthur Gaskin (IRL) 11-7, 7-11, 11-2, 11-0 (36m)
[13] Ong Beng Hee (MAS) bt Mohd Ali Anwar Reda (EGY) 14-12, 6-11, 11-6, 11-8 (68m)
[32] Julian Illingworth (USA) bt Kashif Shuja (NZL) 11-5, 11-8, 12-10 (46m)
[2] Gregory Gaultier (FRA) bt [Q] Alan Clyne (SCO) 11-2, 11-5, 11-7 (27m)
Issued by iSPORTmedia

Kuwait Men’s World Open Championship, Green Island & Salmiya Club, Kuwait
Julian Illingworth, the world No.33 who claimed an unexpected slot as the last of the 32 seeds in the Kuwait Men’s World Open 2009 after the withdrawal of top-ranked Spaniard Borja Golan, took full advantage of his opportunity in the first round match at the Salmiya Club in Kuwait City by becoming the first US player to reach the second round of the premier event on the PSA World Tour in its 33-year history.