Ironically, had the Black Cats' injury curse not struck the midfield, the flame-haired midfield general might never have got his big break.
"It's always the same," Bertschin told safc.com. "For as long as the game's been going people have got chances through other peoples' misfortune.
"Of course we have had a lot of injuries, but that gave Jack his opportunity and I have to say he has been wonderful.
"Jack has made a real case for himself in the first team. Remember, he came into the team in a difficult situation.
"He came in where the team weren't winning, there wasn't a lot of confidence, the pressure was on and it was hard work.
"But he has been brilliant. Jack has proved he can stay in the team on merit."