* Djokovic needs 71 minutes to book spot in second round * Serb says ‘couldn’t ask’ for better start to U.S. Open (Adds quotes) By Larry Fine NEW YORK, Aug 31 (Reuters) – Top-seeded world number one Novak Djokovic raced into the second round of the U.S. Open with a 6-1 6-1 6-1 demolition of Joao Souza of Brazil to close Monday’s first day session at Arthur Ashe Stadium. Djokovic had to wait in the wings for Venus Williams to complete a two-hour, 40-minute win at Ashe, but once the Serb hit the court he played as if he had a taxi meter running outside the National Tennis Center. Ones were wild for Djokovic, who won each set 6-1 in a one hour 11 minute romp to victory for the reigning Australian and Wimbledon champion.