The Hoops take on Benfica in the Europa League in the same city where Jock Stein's side famously defeated Inter Milan 2-1 to win the European Cup in 1967. However, that iconic night remains one of just three Celtic victories in 13 visits to Portugal stretching back more than six decades.

Their overall record on Portuguese soil makes for sobering reading. Since drawing 1-1 with Leixoes on their first trip in 1964, Celtic have won only twice more in the country, beating Vitoria Guimaraes 2-1 in 1998 and overcoming Boavista 1-0 en route to the UEFA Cup Final in 2003.

They have also lost each of their three previous visits to Benfica, going down 3-0 in 1970, 3-0 in 2006 and 1-0 in 2007, before suffering a 2-1 defeat in Lisbon during their most recent meeting in 2012.

Yet Celtic supporters will point to a more encouraging omen. The three occasions they reached the Champions League last 16 this century all came in seasons when Benfica were drawn alongside them in the group stage, with the Scottish champions finishing above the Portuguese giants every time.