Gary 'Spike' O'Sullivan admitted his best wasn't good enough after losing to Jaime Mungui in the early hours of Sunday morning.
The Cork boxer's corner threw in the towel in eleventh round as the Mexican had too much for the 35-year-old.
Victory for Mungui took his record to 35 fights without defeat, while it was the fourth defeat of O'Sullivan's long and esteemed career.
O'Sullivan tweeted today: "It wasn't meant to be for me last night.
"I gave it all I had but it wasn't enough. Thank you everyone for all the support.
"Credit and big respect to @jaimemunguia15 he's a warrior and a great fighter and I wish him all the best in his career going forward."
Munguia, who is the current WBO junior middleweight champion, previously defeated Kildare native Dennis Hogan in controversial circumstances.
His most recent win wasn't free from controversy either as O'Sullivan complained about numerous low blows and a shot to the back of the head.
The referee took one point off the 23-year-old for a low blow in the sixth round, but overall he was the much better fighter in his first bout at the weight.
He caught O'Sullivan with numerous body shots throughout and the Cork native struggled with Munguia's jab.
The win could open plenty of doors for the youngster and he stated afterwards that he wants to fight the likes of Canelo, Gennady Golovkin and Jermall Charlo.
Meanwhile, Spike remains one of the most popular fighters in Irish boxing with his many fans commending his efforts on social media:
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