 Since 2001, Drewett has been the tournament director of the ATP World Tour's season-ending event, the Barclays ATP World Tour Finals.As well as overseeing the event when held in Sydney and Houston, Drewett negotiated a multi-year deal with the Shanghai Administration of Sport and Shanghai Ba-shi Industrial Company to stage the Tennis Masters Cup in Shanghai from 2005 to 2008.On 14 January 2013, Drewett announced he would enter a transitional period as ATP Executive Chairman and President because of illness, after he was diagnosed with motor neuron disease (also known as ALS or Lou Gehrig's disease), writing