The Wales centre produced a stellar performance and scored the last of four Lions tries in the victory.
And Roberts remains thrilled with the achievement as the Lions ended a 16-year wait for series success.
"There are certain things in life that you want to achieve, and the obvious one is to win a World Cup - we (Wales) were desperately close two years ago when we reached the semi-finals in New Zealand," said Roberts.
"But another is to win a Lions series, and you get an opportunity at one or the other every two years, such is the way they are planned out, and they're what you'd like to peak for.
"I've never experienced anything on the pitch quite like scoring in a Test series for the Lions.
"The stadium was so loud and the noise was incredible, but inside it all went a bit quiet. You don't know what to think but it's one heck of a buzz.
"I've had to watch it on replays because you can't really remember a moment like that, but it's a highlight of my career and it'll remain a moment to treasure.
"Tries don't come around too often so to get one in a game of that magnitude and at that moment is a fantastic feeling.
"It was made better by the team performance on the day, and not many people would have predicted that scoreline before kick-off, so it was all the more special to finish the tour in style.
"With Australia winning the second Test, we certainly had the pressure on us, but thankfully came up with what was needed in the game that mattered.
"It dawns on you a bit when you score like that, but I don't think it'll actually hit us for a few months until we realise what we've actually achieved."
Roberts also starred for the Lions in 2009, where he was named Man of the Series and he is already eyeing the 2017 tour of New Zealand.
"There's a lot of rugby to be played between now and 2017, but I'll only be 30," said Roberts.
"Hopefully, that won't be too old to compete at the highest level and for a spot on that Lions tour of New Zealand.
"But it's a long way away and there's a World Cup to be played before then.
"Hopefully, my body will hold up for it!"
But before any World Cups and Lions tours, Roberts must tackle the newest chapter in his career.
Having completed his medical studies the burly centre has swapped Cardiff Blues for Racing Metro and he is relishing the challenge.
"The plan now is to have a short break in Marbella with a few good friends from back home, and then it's off to Paris to find a place to live," added Roberts.
"I've got my graduation at Cardiff University and then I've got another short holiday that I haven't decided yet, maybe somewhere like Croatia for a few days.
"But then the focus is on Paris and doing my best to settle in with my new club Racing Metro.
"I'll miss living in Wales hugely, but I'm ready to go abroad and challenge myself.
"It's taking myself out of my comfort zone and right now the move is really exciting.
"I've done well in Cardiff and finished my education, so it's the perfect time to make the change, spread my wings and try something new with the massively exciting challenge that awaits."