Former world No.1 tennis player Juan Carlos Ferrero has been coaching Germany’s rising star Alexander Zverev since July this year and both are currently in London for the Nitto ATP World Tour Finals at the O2 arena. The Spaniard reached the top ranking in September 2003 after winning Roland Garros and runner-up at the US Open. Nicknamed ‘El Masquito’ because of his speed and small build, Juan Carlos was also part of three winning Davis Cup campaigns for Spain. He signed my sketch at the O2 on Saturday.