Cesc Fabregas
One of the best incoming transfers during Wenger's tenure, but also one of the toughest outgoings - losing Cesc Fabregas to Barcelona at his peak was a difficult one to take.
Fabregas won six major honours in three years upon his return to Catalonia, yet it was in the English capital where he grew from a boy into a man, with an FA Cup winner's medal to show for his efforts.
The creative midfielder set Arsenal back a compensation fee of £500,000 and was sold back to Barcelona for 70 times that amount, having made over 300 appearances for the Gunners in between those two deals.
Further disappointment would follow for Wenger as Fabregas opted for Chelsea, rather than Arsenal, when returning to the Premier League in 2014 to continue his love affair with the English game.
