"The Rugby World Cup is the pinnacle for every referee and selection has been my goal for the last three or four years, so it's a great personal achievement for me," he told the tournament website.
"It was an honour to get selected, but I never contemplated being selected for the opening match. It was a major bonus. To be entrusted with the opening match is a huge honour and something that I am really looking forward to."
It was in June 2008 that the Limerick native refereed his first top-ranking Test match between South Africa and Italy, just a couple of months after joining his Irish colleagues Alain Rolland and Alan Lewis on the IRB Referee Panel.
His Six Nations refereeing debut followed in 2009 and he continued to develop his command of games at domestic, European and international level.
The 34-year-old civil servant maintained his presence on the world stage last year, with Test appointments in Wales, Fiji, New Zealand, Australia and England.
He refereed a Heineken Cup semi-final and the Amlin Challenge Cup final last season and was the man in the middle for South Africa's Tri Nations win over the All Blacks in Port Elizabeth last month.
Having worked hard to ensure he is in 'top form both physically and mentally', his World Cup bow in Auckland cannot come quick enough.
"It's a massive challenge but I've prepared thoroughly, with the Referee Manager and my fitness coach. I want to referee to the best of my ability and also enjoy the experience."
Clancy's love of rugby was fostered at St. Munchin's College, where Marcus Horan and Jerry Flannery were fellow pupils, and Bruff RFC.
He turned out as an out-half or full-back for Bruff and still holds close ties with the Ulster Bank League club.
Hurling was the first sport that he took to as a youngster but he gradually sought out the oval ball due to his father Seoirse's involvement with the Community Games and rugby.
He continued to play both sports and won a Munster Junior Challenge Cup title with Bruff in 1998, until 'a few knocks' contributed to his decision to quit rugby.
His dad, a referee himself, convinced him to give refereeing a go and he was taken under the wing of Johnny Cole, one of the Munster Referee Recruitment Officers, in 1999.
His first match as a referee followed in October 2000. It was an Under-15s' league clash between Richmond and Garryowen which ended in a 0-0 draw, the only scoreless game of his career - so far!
Clancy made his way up from underage to Munster Junior League and then All-Ireland League, where he benefited from the tutelage of the two leading figures in IRFU refereeing circles, Dave McHugh and current IRFU Director of Referee Development Owen Doyle.
With an IRFU contract secured, his progress continued and the hard work put in both on and off the pitch - he trains in the University of Limerick with regular weights and speed sessions and aerobics - has led him to the top of the refereeing tree.
He will no doubt have been in touch with some of his friends from the Irish refereeing fraternity this week, and he paid tribute to two of the trailblazers before him, one of them being Alan Lewis who hung up his whistle at the end of last season.
"I have been very lucky to be able to learn from (Alain Rolland and Alan Lewis), two of the top referees in the game," he added.
"I performed the assistant referee role for them as I was coming up through the ranks and I'm very lucky to have been able to draw from their experience."
The highly-regarded Rolland is on assistant referee duty for Saturday's match between France and Japan in North Shore, and the following day he will referee the meeting of Ireland's Pool C rivals, Australia and Italy.
Another Irishman Simon McDowell, who is at his second World Cup, will begin his assistant refereeing roster with the Argentina v England tie in Dunedin on Saturday.
When Clancy blows the first whistle to get the opening game of the 2011 tournament underway, it will mark the continuation of a Rugby World Cup tradition.
The same whistle has been used to start the opening match of every Rugby World Cup, while a single florin has been used for the coin toss at those fixtures.
The whistle was used by Welsh referee Gil Evans for the 1905 All Blacks tour to Britain and Ireland, who later presented it to compatriot Albert Freethy. The latter used it to officiate in the rugby final of the 1924 Olympic Games and again for the New Zealand-England clash at Twickenham in 1925.
It was at that game New Zealand supporter DC Gray lent Freethy a coin for the toss, later having it embossed with a rose and a fern to mark its significance.
Outside of Rugby World Cups, the two items are kept at the New Zealand Rugby Museum in Palmerston North.
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