By Julien Pretot PARIS, Oct 30 (Reuters) – World number one Novak Djokovic, who will defend his Paris Masters title next week, says he is fully motivated again having felt mentally drained since his French Open success in June. The Serbian has won only one tournament, the Toronto Masters in July, since completing the career slam at Roland Garros. Djokovic was knocked out of Wimbledon in the third round, the first time he had failed to make it through to a grand slam final since the 2014 U.S. Open, before being eliminated in the first round at the Olympics.