Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: World No 1 Novak Djokovic barely broke sweat as he dispatched Brazil's Joao Souza for the loss of just three games in the US Open first round. Djokovic is gunning for his third grand slam title of the year after triumphs at the Australian Open and Wimbledon, and the Serb put on a dominant opening display in New York to win 6-1, 6-1, 6-1. The victory took just one hour and 11 minutes to complete, with Djokovic now up against either Canada's Vasek Pospisil or Austrian Andreas Haider-Maurer in round two. Djokovic arrived in Flushing Meadows with some question marks hanging over his form following defeats in consecutive weeks to Andy Murray in Montreal and Roger Federer in Cincinnati.World No 1 Novak Djokovic recorded a 6-1, 6-1, 6-1 victory in New YorkAustralian Open and Wimbledon champion chasing third grand slam title 
 Question:The top seed, however, often saves his best for the heat of a grand slam and he never had to leave first gear against _, who is ranked 91st in the world and looked out of his depth from the start.
Output:
Joao Souza