O'Neill regrets Norwood's decision to retire from international football

The 28-year-old midfielder -- most of whose 57 caps have come under O'Neill -- said he wanted to focus on his club career with Sheffield United, who have made an encouraging start in their return to the Premier League.

However, O'Neill said Norwood -- who was part of the squad that reached the last 16 of Euro 2016 -- had the ability to go on and achieve great things with his country.

"I think he is making a huge mistake," said O'Neill.

"He is only 28 and I've no doubt he could have continued to play club and international football for many years.

"Ollie has been a mainstay of our team for the past seven years.

"I know this was not an easy decision for Ollie to make, however I think his decision is premature.

"He had the opportunity to leave an incredible legacy at international level and the potential to reach 100 caps."

England-born Norwood -- who made his international debut in 2010 -- said he had enjoyed his time being part of the Northern Ireland squad.

"After proudly representing Northern Ireland on 57 occasions, I feel now is the right time to announce my retirement from international football," he said in a statement issued by his club.

"I've enjoyed the highs of a major tournament -- being part of the squad in France at Euro 2016 was the proudest point of my international career.

"I would like to thank the manager, Michael O’Neill, for selecting me on so many occasions to represent my country, and also to the players I've played with through the years.

"We've had some enjoyable times."

O'Neill for his part said he was confident the players he had available for selection would secure their qualification for next year's finals.

They have won all four of their qualifiers thusfar -- they top the group -- but are yet to play established European powerhouses Germany or The Netherlands. 

"Ollie will be a loss to our squad, however we have won our four qualifying games to date (for Euro 2020) in his absence and the squad will continue to progress," said O'Neill.

"I believe the players in my squad are more than capable of reaching another major tournament."