* Giggs retires from playing after 23 years at Manchester United
* Will focus on role as assistant to new boss Louis van Gaal (Adds detail, quotes)
By Mitch Phillips
May 19 (Reuters) - Ryan Giggs has called time on his remarkable 23-year, trophy-laden Manchester United career to commit himself to his new role as assistant to manager Louis van Gaal, who was confirmed as the successor to David Moyes on Monday.
Giggs, who made a record 963 appearances, winning 13 league titles, four FA Cups and two Champions League trophies, announced his decision on Monday via an open letter on the club's website.
"I would like to take this opportunity to announce my retirement from professional football and embark upon a new and exciting chapter in my life," 40-year-old Giggs said.
"I am immensely proud, honoured and fortunate to have represented the biggest club in the world 963 times and Wales 64 times.
"My dream was always to play for Manchester United and although it saddens me to know I won't be pulling on a United jersey again as a player, I have been lucky enough to have fulfilled that dream playing with some of the best players in the world, working under an incredible manager in Sir Alex Ferguson, and most of all, playing for the greatest fans in world football.
"I have always felt and appreciated your support. I would not have won 34 trophies in my career without you."
Giggs made his United debut in 1991 and remained an integral part of the club under Ferguson as they established themselves as the dominant force in English soccer.
Initially a wiry, close-dribbling winger, his midfield combinations with the likes of David Beckham, Paul Scholes and Roy Keane were at the heart of much of the team's success.
His amazing superb solo goal in the FA Cup semi-final replay against Arsenal in 1999 - en route to United securing the treble of league, FA Cup and Champions League - has been voted the club's greatest goal by a poll of fans.
Giggs' international career was not so successful as he performed in a Wales team which failed to make a major championship - despite some near misses - while his relationship with Wales fans was strained by his regular withdrawals with minor injuries that would miraculously disappear in time for him to resume United action days later.
He retired from international football in 2008 though did, however, enjoy a swansong of sorts when he captained the British football team at the 2012 London Olympics.
As he aged, Giggs developed into more of a soccer quarter-back, less mobile but able to spread passes with deadly precision while giving a masterclass in keeping possession.
Ferguson routinely paid tribute to Giggs' committed approach to fitness and "fuelling", and how they helped him continue to operate at the very top level at an age when most of his contemporaries had long retired.
With the departure of Ferguson at the end of last season, Giggs became a peripheral figure under Moyes but was thrust back on to centre stage as player-manager for the last four games of the season after the Scot was sacked.
He selected himself for only one of them - a substitute appearance in the 3-1 victory over Hull City at Old Trafford in the penultimate game of the season.
"For me, today is new chapter filled with many emotions - immense pride, sadness, but most of all, excitement towards the future," Giggs said on Monday.
"United fans I hope will share and echo my belief that the club, the management and owners, are doing everything they can to return this great club to where it belongs, and I hope to be there every step of the way." (Editing by Justin Palmer)