Inter and Napoli suffered major setbacks in the Champions League on Tuesday, with the Milanese side losing 3-1 at San Siro to Arsenal and the Serie A champions being held to a 1-1 draw by 10-man Copenhagen away from home.     Inter were sunk by double by Gabriel Jesus and a late strike by Viktor Gyokeres as the London side maintained their perfect record in the group stage of the competition.     The loss means Serie A leaders Inter have dropped out of the top eight, which guarantees a slot in