The 24-year-old defender became manager Paolo Di Canio's 10th signing of the close-season on Tuesday when he agreed a season-long loan from Trabzonspor.
Celustka spent two years in Turkey after moving there from Slavia Prague in 2011.
He made 55 appearances in the Super Lig and reached the Turkish Cup final last season, but could not resist the lure of the English top flight.
"Every match against clubs from the top of the Premier League table is like the Champions League," he told www.idnes.cz.
"The whole world is following this competition and together with the German Bundesliga, they are the best leagues in the world."
Celustka was impressed after his first training session under Di Canio and looking forward to playing for the Italian.
"In the first training session he automatically put me at right-back and I had a good feeling about it," he added. "He wants me to get used to the team as fast as possible.
"They are regular members in the Premier League. So far from what I have seen, the facilities are on a high level and the stadium is beautiful.
"They have about 40,000 fans attending every match and so far Sunderland have made the best impression on me."
