Connecticut United Übersicht

Massimiliano Allegri has warned his Napoli side that they are coming up against one of the best teams in world football as they prepare to host Arsenal in their Champions League opener. The Italian tactician identified a specific tactical evolution under Mikel Arteta that has transformed the Gunners into a formidable European force.

Several high-profile stars have been left out of European squad lists following key deadline decisions. From Liverpool's Federico Chiesa and Real Madrid's Ferland Mendy to Borussia Dortmund captain Emre Can, managers across the continent faced tough selection calls due to injuries and squad limits.

The road to Madrid begins this week as the league phase gets under way - but which teams are currently looking in the best shape to go on and lift the European Cup?

Bruno Guimaraes has offered a fascinating insight into the mentality of Mikel Arteta, describing the Arsenal manager as "very obsessed" with continuous improvement. The Brazilian midfielder, who arrived in North London this summer, believes the Spaniard's relentless drive is the primary catalyst behind the Gunners' perfect start to their Premier League title defence.