It has been a big week for new Celtic talent Arne Engels, who not only completed a record move from the Bundesliga to Scotland but made two debuts in six days. The new Bhoys midfielder arrived at the club for £11m on deadline day before making his first appearance in green and white during the 3-0 derby win over Rangers. On Friday night, he took a big step forward on the international scene, too, making his debut for Belgium. Engels replaced upcoming Champions League opponent Youri Tielemans in the 73rd minute, earning his first senior cap after representing his country in every youth age grou…