By David Anderson Kai Havertz claims Arsenal have proved they were right not to splash the cash on a striker in the last transfer window. Mikel Arteta was urged to buy a top goalscorer after Arsenal netted just five times in their seven games, culminating in their FA Cup defeat to Liverpool. They scored just once in the back-to-back Premier League defeats to Fulham and West Ham and the critics said Arsenal could not win one of the game’s big prizes without a proven marksman. A sunshine training camp in Dubai sorted them out and the on-fire Gunners have banged in 21 in their last five games. Ar…