Back then, it was only the second time in 20 years that the law faculty had awarded first-class honours to more than one candidate.
That propelled him to start an academic career as a senior tutor and, later, law lecturer at NUS until 1998.
Looking back now, the Rajah & Tann managing partner said: "I found that I went into academia too early. Nowadays at my age, I wish I could go back to academia.
"For the six years, I benefited greatly, but to continue beyond that, I don't think I would have grown (in my career) very much because I had not practised yet."
Armed with a solid foundation of the law, Mr Lee, 48, decided to move into private practice and joined Rajah & Tann - one of the largest law firms here - as a partner on June 1, 1998.
This year, the firm celebrates the first anniversary of Rajah & Tann Asia, the largest legal alliance in South-east Asia. The network has eight firms with more than 500 lawyers from nine countries, including Malaysia and Myanmar.
He said: "That is a path we have been taking for the past five to six years. We knew that if we wanted to remain an independent Asian firm, we had to do something more than being one of the top firms in Singapore."
The firm was also recently named Singapore National Law Firm of the Year by Chambers Asia-Pacific.
Singapore is a mature, sophisticated and competitive market, and is still Rajah & Tann's anchor market, said Mr Lee, but the growth rate outside Singapore is "nothing like what we will ever see here again".
Rajah & Tann expects to send more Singapore lawyers out into the region to cope with demand.
"In places like Indonesia, for instance, the growth is significantly higher than in Singapore," noted Mr Lee, who added that these are markets on the rise.
Non-Singapore work already makes up about 40 per cent to 50 per cent of total revenue.
Mr Lee's rise has been fast. He headed the firm's restructuring and insolvency practice group from 2003 to 2009.
In 2008, he was appointed Senior Counsel. Two years later, at 43, he was appointed managing partner, making him one of the youngest managing partners of a law firm here.
In 2011, Rajah & Tann became the largest practice in Singapore and South-east Asia.
Much of the credit for transforming Rajah & Tann into a leading law firm in the last couple of years goes to Mr Lee, although the foundation was laid by former managing partners V.K. Rajah, now Singapore's Attorney-General, and Chief Justice Sundaresh Menon.
Mr Lee has always found himself drawn to insolvency law, a passion sparked by his pupilage days at Rajah & Tann in the 1990s.
That was the era of one of the most spectacular crashes of modern times, when Britain's venerable Barings Bank collapsed, thanks to Singapore-based rogue trader Nick Leeson.
He said: "I just happened to find myself in Rajah & Tann under V.K. Rajah and Sundaresh Menon. They were advising and acting for the judicial managers.
"And it was such a stroke of luck I got to see all that first-hand. I was drawn into it."
After he was conferred the title of Senior Counsel, it was a natural progression for him to take up more commercial litigation cases.
He noted that it is part of his role to represent the firm's clients who want a Senior Counsel to handle their cases.
Mr Lee said: "The insolvency team had matured and the people I had worked with as juniors had become lead partners in their own right, so they could run the insolvency practice."
He added: "I expanded my insolvency and banking disputes practice to include commercial litigation and arbitration, and I have done a good mix of cases for the last seven years."
In that time, he represented surgeon Susan Lim, who was charged with professional misconduct over the amount she charged a royal patient from Brunei.
Dr Lim was given a three-year suspension and fined $10,000.
Mr Lee recalled: "Of course, I could not get the result that I wanted to deliver to her.
"But to be able to be with her and her husband through that experience, and trying my best to advance that case for them, and in the course of doing that, having to really analyse the issues that were not strictly legal, the policy and regulatory angle, it was one of the more interesting cases of my career."
There are days when he misses academia, given the freedom he had in areas such as research.
"The main draw of academia is being able to research and write on anything that catches your fancy."
However, he enjoys going to court. He said: "There is a thrill and satisfaction in applying all your intellect, professional skills and energy towards advancing a case for your client in court or in arbitration, and being an integral part of a fair, orderly and efficient dispute-resolution machinery."
Fellow lawyers said Mr Lee is an intelligent leader who has piloted Rajah & Tann's expansion in recent years.
Rajah & Tann Senior Counsel Andre Yeap said: "It has been a unique and rare privilege to have been able to witness the phenomenal growth of Eng Beng as a young lawyer within the firm to the bastion of strength, drive, fortitude and high legal intellect which he has become."
He added that the managing partner's "energetic, determined leadership drive in expanding Rajah & Tann's footprint across nine countries in the space of a few short years to become South-east Asia's largest law firm is a lasting legacy to the regionalisation and internationalisation of the legal profession in Singapore".
Mr Patrick Ang, Rajah & Tann's deputy managing partner, said of Mr Lee: "He is wonderful to work for because he is a very down-to-earth guy and everyone respects him for his skills as a litigator and Senior Counsel."
Mr Lee is known for being a visionary, said Mr Ang, "not just for the firm, but also for the young lawyers and what they should be preparing for... to be more cross-border in the way we practise as Singapore lawyers".
He noted that before Mr Lee took the helm, about 90 per cent of the firm consisted of locally practising lawyers. Under his leadership, about one-third are practising offshore. "The firm has transformed its practice under his leadership," said Mr Ang.
That is why, for now, Mr Lee is focused on the firm and its business. Also, the legal sector is at a both exciting but challenging juncture, where Singapore is keen to grow its arbitration business.
Mr Lee said: "I hope Singapore continues to excel in its quest to be one of the leading international arbitration hubs in the world.
"Not only is it a source of pride and inspiration for all of us in the legal community, it brings opportunities for us to be
exposed to and work on the biggest and most exciting international disputes."