Ireland's Andy Lee became the WBO middleweight champion on a memorable night in Las Vegas.

In the biggest fight of his career, Lee delivered in some style and knocked out the previously undefeated Matt Korobov at the Cosmopolitan Hotel.

The 30-year-old, who formerly worked under famous trainer Emanuel Steward, stunned his opponent with a right hand and then moved in to finish the job in the sixth round.

Lee was behind on all three judges scorecards before delivering the final blow but had rarely looked to be in serious trouble.

It is a remarkable achievement for Lee and his new trainer, Adam Booth, and one that is sure to earn him bigger fights and recognition.

"It's tough to describe this moment," he said to the media afterwards. "I am a champion and I want to defend my belt in Ireland and I will fight the best in the world.

"We were trading and a lot of the times he was having the better of it but my right hook is a killer punch. I thought he was going down but I wasn't taking any chances,"

"I've never been hurt before but he got me with a tremendous hook," Korobov said. "I was stunned. I couldn't continue."

Lee paid tribute to his late trainer Steward, who coached the likes of Thomas Hearns, Lennox Lewis and Wladimir Klitschko before his death in 2012, and had taken Lee, from Limerick, under his wing.

"I have to say a thank you to this man, my coach Adam Booth, who has done so much for me in the last couple of years - this title is for him, but also for the man who made me, Emanuel Steward," said Lee.

What happens in Vegas...Gets taken back to Ireland. Andy Lee... WBO WORLD MIDDLEWEIGHT CHAMPION! My proudest moment! pic.twitter.com/dSWKLl9BKg
— Adam Booth (@boxingbooth) December 14, 2014

The pair lived together and Steward had tipped his man for big things.

"I lived with him for seven to eight years and learned so much from him. He said I would win a world title and tonight I made it true," Lee added.

"Up the Irish. Get in!"

Booth, who coached David Haye to the heavyweight championship of the world, added on Twitter that it was his "proudest moment".

Billy Joe Saunders, who beat Chris Eubank Junior on a split decision in November looks set to be Lee's opponent for his first title defence as he is the mandatory challenger.

Congratulations Andy