"Every week I think about the missed opportunity in 2009. It burns in the back of your mind until the next tour," admits Roberts, who will line-up against the Barbarians in the opening game of the 2013 tour.
"I will always remember that season of 2009 as one of 'what ifs'. As a player I was in a Heineken Cup semi-final team that lost in a penalty shoot-out; with the last kick of the game against Ireland, Stephen Jones fell about a metre short in a match that gave the Irish the Grand Slam and then the second Test at Loftus was just the final nail in the coffin.
"It was one of those seasons. The two memories for me from the 2009 Lions tour were running out for the first Test in Durban and seeing all those red shirts.It was like playing at home. We played a lot of good rugby in the second half, but we just left it too late.
"And then the second Test - and the hospital waiting room, when there were five of us waiting in outpatients just sitting there shaking our heads in disbelief.
"I'm always asked in interviews about the changing room after that second Test. It was unlike anything I had ever experienced and, four years later, I've still never experienced anything like it, losing a game of such huge significance.
"We have a chance to put it right on this tour and we are all desperate to recreate what the Lions did in 1997. We came so close in 2009.
"When I look back on 2009 I feel I played some of the best rugby of my career in a Lions shirt. That's what I want to recreate and, ultimately, I want to win a Lions series with these guys."
Roberts will once again get a first shot at laying down a marker for a centre spot against the Qantas Wallabies when he links up with his Welsh midfield partner Jonathan Davies in Hong Kong. He knows all about first night nerves having been in the side that scraped home against the Royal XV in Rustenburg four years ago.
"I remember that game well and we almost lost it. We came through in the 75th minute with a little chip and chase from Lee Byrne," recalled Roberts.
"A lot of us were forcing things and it is important against the Baa-Baas that we put into practice what we've been doing in training. Having trained for three weeks all we want to do now is play.
"The tour kicks-off after our first game and it is important we set the standard for the next team to carry on. I always remember from 2009 that we never wanted to fall below the performance from the previous game and wanted to try to keep raising the bar to the test matches.
"The standard we set in Hong Kong will set the tone for this tour. Training has been tough and we have trained at an intensity to make it tough.
"The conditions will be very hot and humid, and not what we are used to, so it will be very demanding on the body. The water breaks will be very important from a health and safety point of view for the players, but also to ensure the quality of the rugby is good enough to make it the spectacle we all want it to be.
"Dehydration, electrolyte imbalance and overheating are all potential risks, so the water breaks will be very important. The conditions are quite alien to the players, but the water breaks are there for their health and safety and, hopefully, they will keep us fresh."
A big performance in Wales' record breaking 30-3 RBS 6 Nations win over England cemented Roberts' place on the tour and he is one of 13 players in the squad who have toured with the Lions before. But he knows he cannot rest of his reputation if he wants to make the Test team.
"I like to peak for the big games - I really thrive on them. The bigger the occasion the bigger the pressure I put on myself to perform," he said.
"The coaches have hammered home the fact that everyone is back to square one and what has gone before doesn't matter. It is all about what happens on this tour.
"There is huge competition for my position, that's no secret, and Jon and I have a chance to lay down a marker, but I'm sure Manu and Brian will come in and try to raise the bar the next week.
"Every individual will have goals of being in the Test side, but it is important as units that we go out and play as a team. The ultimate challenge for the Lions is to get everyone singing off the same hymn sheet right from the first minute.
"Preparations have been similar, if not better, than four years ago and I feel within the squad that we are ready to go. The first week of training in the Vale went well and then it went very well in Dublin. In fact, we were ready to play a week ago.
"Everyone has had a great laugh in the past few weeks. We've been working hard, but first and foremost we are enjoying ourselves and hopefully that will be reflected in the way we play.
"After their result against England it wouldn't surprise me if the Barbarians play a tighter game and play with more structure. Having worked under Dai Young I know the way he likes to play.
"The Barbarians are notorious for chucking the ball around in their own half, which will challenge us defensively, but coming off that scoreline last weekend it wouldn't surprise me if they played a completely different game.
"We are expecting a huge reaction from them. We are aware of their defeat last weekend and the things that have been said about them, but they have a huge amount of talent - there is a lot of international quality and experience in their team."