Iron man Josip Juranovic admits he conked out for 14 hours after a gruelling international break with Croatia.
But he's delighted to have earned undroppable status for his country - and says he has Celtic 's relentless style of play to thank for it.
The 26-year-old linked up with his country after a spell on the sidelines for his country but he was one of just two players to play EVERY minute in their four Nations League games - along with Inter midfielder Marcelo Brozovic.
Central to his importance was his ability to play on both flanks - a similar dual role to the one he played last season under Ange Postecoglou.
The full back helped his country to an impressive series of victories during the summer where they won away in France and Denmark and kept two clean sheets in those games too.
He also played against France and Austria at home and was one of only two Croatian players who played all 360 minutes of the group games.
But he admitted he was exhausted after the end of the gruelling series of games
Juranovic said: "When we got home, I slept from 4.30pm until 6.30am in the morning. And I could still have slept more.
"I didn't even train for six and a half weeks, I needed to get back to my previous form, but the more I trained and played, the more stable I became. I also thank the manager for inviting me, supporting me and being with me.
"That was my 20th cap for Croatia and I have enjoyed a lot of success. I just want to win as many caps as I can.
"We play a little differently at Celtic than I was used to playing before, I have more muscles in my legs and I think I have become fitter and a better player.
"I have got more self-confidence now and I think you could see that in Paris.
"I'm in Split at the moment, then I'm going back to Paris with my girlfriend. I have two full weeks off.
"But I think when the new season starts, everyone in our squad will have to be at their best because competition will be intense for a place in the squad for Qatar.
"I just hope there are no injuries before the World Cup."
