Northern Ireland boss Michael O'Neill disappointed with referee Marian Radu Petrescu following Slovakia friendly

Defender Craig Cathcart was forced off after half an hour after taking a knee to the back.

Striker Kyle Lafferty was also replaced after he picked up a calf injury.

Slovakia’s no-holds barred approach was surprising given both teams would have wanted to advance to France without any injury concerns.

And O’Neill, whose side face Poland, Ukraine and Germany in Group C at the Euros, was disappointed that Romanian official Petrescu didn’t produce more yellow cards.

“They’re playing at home, the stadium’s full and off the back of (the 3-1 win in) Germany, I’m sure they wanted to give the supporters a send-off and win the game,” O’Neill added.

“I felt that some of the challenges under normal circumstances would have been punished with a yellow card but weren’t. I thought the referee was lenient in favour of the home side at times. That’s understandable.”

That Slovakian approach did pave the way for Hughes to join Pat Jennings in his country’s century club half an hour into the game.

There was no ceremony or celebration as he dashed in to defend a corner and O’Neill was delighted that a 36-year-old player used sparingly by club side Melbourne City last term showed he can still cut it on the international stage.

“It’s fitting that Aaron is the first outfield player to gain 100 caps,” he said.

“He didn’t want it given to him and it certainly wasn’t given to him tonight. He had to go on in difficult circumstances. My plan was to introduce him at some point in the game and I was actually delighted that I did put him on in the situation we did.

“It’s important that we know he’s still ready and he certainly showed that. He’s not played a lot of football in Australia this year but what he has done, his focus has been to be ready for the finals.

“You see the reaction of the players in the dressing room with him, what it means for a player like Aaron Hughes to be part of this squad and to reach 100 caps.”

Slovakia’s win over the world champions last Sunday had raised eyebrows across the continent, though they were unable to make another statement before they join a group with Wales, Russia and England in France.

“They were two different matches, obviously,” coach Jan Kozak noted.

“We play there in different positions – home and away – in both matches we had to be cautious, especially in the defence. Nevertheless, I believe our players are very dominant, they are able to play and I hope they will show this in Euro 2016.”

Meanwhile, Kozak may be excited about a meeting with Wales’ Gareth Bale next weekend, but the Real Madrid fan joked it will be the forward asking him for an autograph after their Euro 2016 opener.

“Clearly he’s a top player, one of the best in the world, so we are looking forward to meeting him. Personally, I’m a fan of Real Madrid so I’m personally looking forward to that,” he added.