However, soon after their success in reaching the semi-finals - with the duo in peak form - Reginald suffered two serious injuries, which left him unable to play for nine months.
Although the two 17-year-olds are back playing together at this year's Badminton World Federation World Junior Championships, which start in Taipei, Taiwan, tomorrow, they are unsure about their chances.
"We have been training together for only a few months [since the injury] and don't want to put ourselves under any pressure because of expectations," says Angus, who is a student at Diocesan Boys' School, in Mong Kok.
"All of our main opponents will have been able to improve a lot in the past 12 months. But just like last year, we will be aiming for the quarter-finals. Any victories after that will be a bonus."
The pair, who are Hong Kong's first world junior doubles medallists, were delighted with their display when they resumed competitive action at last month's Vietnam Grand Prix, which features senior players. They gained some much-needed confidence despite being narrowly beaten 20-22 and 15-21 by the top-seeded Japanese pair of Hirokatsu Hashimoto and Noriyasu Hirata, who are ranked number 10 in the world.
"We played well and believe that we don't have big problems with our game, despite not playing together for so long," Angus says.
Angus and Reginald started playing doubles together in 2006 after being evenly matched in singles at numerous tournaments over the years.
Reginald admits to being frustrated by his injuries, which came soon after he chose to become a full-time professional player after completing Form Three at La Salle College, Kowloon.
"My memory of injuring my left ankle is still fresh in my mind," Reginald says. "I will never forget the day I got injured - August 18 last year. I twisted my ankle during training and at first I thought it was only a minor injury. But it was still really painful after putting ice on my ankle to reduce the swelling. I had it examined by doctors and found that I had a crack in my ankle bone."
He could have recovered more quickly if he had chosen to have surgery, but he decided he did not want to take the risk. He preferred to let the ankle heal naturally, which took six months. But only a few days after getting back on court, he suffered a knock to the same ankle. The bruising and swelling took a further three months to heal properly.
"I feel as if I have wasted more than half of my two years as a full-time professional," Reginald says. "And I am unhappy that I got hurt just when I was starting to have outstanding results with Angus."
Reginald often went to watch Angus and other players train even though he was unable to take part himself.
Angus says he felt terrible seeing Reginald limping around using a walking stick. "Reginald is usually so energetic, so I knew he must be feeling really upset," he says. "My coach knew Reginald was unhappy and needed my support. So I spent a lot of time chatting with him and trying to make him feel better."
The duo's close bond has helped Reginald's slow return to the sport. "It has felt discouraging," Reginald says. "I had improved the weakest part of my game - my fitness - before I got injured. Now I have had to start all over again. I hate track running during fitness lessons, but I know I need to do it.
"Things were tough for me when I started back this summer, but now it's easier. I am also lucky this year's world championships are in October. If they had been in July, like last year, I would not have been able to play."
Their doubles partnership may be resuming only for a short time, however. Angus, who wants to go on to university, is keen to focus on playing singles, while Reginald wants to concentrate on doubles tournaments. Angus will also be focusing on his HKDSE examinations after this month's event.
So the duo might be dissolving their partnership soon.
"The Thomas Cup - the world men's team championship for seniors - is coming up next year," says Reginald. "I don't know what will happen, but it would be really great if we could be playing in that together."