Top seeded Victoria Azarenka of Belarus prevailed in the women's draw, as did Venus Williams and Maria Sharpova.
They all reached the round of 16 as play was delayed for the second time in three days by the elements. Once the rain stopped, most of the scheduled action was completed and there were no dramatic surprises as the top tennis players in the world competed for the second time in a month on the courts of Wimbledon.
Djokovic, of Serbia, lost his world No. 1 ranking to Roger Federer this year but he was in excellent form Tuesday while downing Roddick 6-2, 6-1. They played their match under the roof of Centre Court at the All England Club.
Wimbledon runner-up Andy Murray of Britain made short work of Marcos Baghdatis of Cyprus, but there was nothing short about the win posted by Tsonga.
The Frenchman outlasted Canadian Mikos Raonic 6-3, 3-6, 25-23. The final set took three hours to complete and the players engaged in a weary, congratulatory hug after the match.
Williams will meet her sister Serena in the semifinals if they both win two more matches.
Sharapova was one of the players who had the benefit of playing on Center Court so her schedule was not disrupted by the rain. The Russian won over Laura Robson of Britain 7-6, 6-3.
Julia Goerges of Germany, who upset second-seeded Agnieszka Radwanska of Poland in the first round, advanced again with a 6-3, 7-5 victory over Varvara Lepchenko of the United States.