For example, he has had one competitive game in charge of Celtic and the opposition, a little club in Iceland, included Luis Suarez's brother-in-law.
KR Reykjavik's No.4, a 22-year-old left midfielder Gonzalo Balbi, is Uruguayan. His sister, Sofia Balbi, was Suarez's childhood sweetheart and became his wife. Suarez and the Balbis go way, way back.
"I spoke to Luis before the match," said Gonzalo after Reykjavik's 1-0 defeat to Celtic in the first leg. "I talk to him a lot. I've known him since he was 15 so we go back a long way. He couldn't come to the match because he's back in Barcelona sorting things out. I think he has much more important things on his mind right now! But, of course, it's nice to know I can call him anytime, he helps me a lot."
In return, Suarez has his unwavering loyalty. There is one quite well-publicised reason why Suarez could not have attended his brother-in-law's game against Celtic: it would breach the infamous nine-game, four-month FIFA punishment which banned him from all football-related activities for biting Giorgio Chiellini.
"Luis is a great guy," Balbi added. "He has a very bad image right now because of what happened in the World Cup but he's not like that at all. He's now one of the best in the world but, believe me, he's had to fight for everything he has in his career."