Watching the World Cup? Check out this cool video about how goal-line technology works and why it's so effective.
Arsenal will likely have to sell one of Petr Cech or David Ospina this summer given that they have completed the signing of Bernd Leno from Bayer Leverkusen.
The Gunners were below-par defensively last season as they endured one of the most frustrating seasons in the modern era.
Leno will arrive at the Emirates Stadium with an impressive reputation and could even start the new season as first-choice goalkeeper.