Johnny Sexton says retirement is already proving "so tough" after his career came to a close following Ireland's World Cup exit.

"But the overarching feeling is the pride I felt playing with such a committed and talented group," he said.

"Leaving these players and coaches is what is making retirement so tough."

Sexton, 38, prolonged his career into a fourth World Cup and Ireland went into the tournament ranked as the world's top team, only to fail to progress beyond the last-eight stage as they were edged out 28-24 by New Zealand in a thrilling contest in Paris.

"Retirement is never an easy next step for any professional athlete. It is especially hard after the rollercoaster of emotions from the last few weeks in France," added the former fly-half, who won his 119th cap for Ireland in the defeat by the All Blacks.

"I've said it many times before but there's no feeling like playing in front of a home Irish crowd and that's what it felt like in Bordeaux, Nantes and in Paris on those three special Saturdays [during the World Cup].

"I want to thank my team-mates, both for Leinster and Ireland, for everything they have given to me.

"The last season was one of the most enjoyable of my career and it makes it even more special to do so with people you care about, friends who will stay a part of my life in the future."

'We lost but we won'

Sexton listed those he felt have made a significant contribution to his life as a rugby player.

"To all the teachers, coaches, support staff and all those who encouraged and supported my career starting out in Bective, St Mary's College, club and school, for over 30 years, thank you for everything," he wrote.

"To the supporters of Leinster, Racing, the British & Irish Lions and Ireland - with whom I was proud to share my journey - thank you for your faith and unwavering support.

"To my family, my parents, brothers and sister who nurtured my love of the game and instilled my drive, I couldn't have made this journey without you.

"Finally to my wife Laura and our children, your unconditional love helped inspire me through the ups and downs of life and I am incredibly excited about our next chapter together. By far my proudest moments were getting to play with my kids watching on."

Sexton finished his statement by saying how the Ireland players, in the wake of their World Cup quarter-final hammering by New Zealand in Japan four years ago, had "sat down as a squad" and resolved to "inspire the nation".

"I think we achieved that," he added. "We lost but we won."