Seven-time champion Roger Federer and three-time winner Novak Djokovic registered straight set victories to enter the third round of the Wimbledon tennis tournament here.Federer, who turns 36 next month, won 7-6 (0), 6-3, 6-2 at Centre Court while Djokovic eased past Adam Pavlasek of the Czech Republic 6-2, 6-2, 6-1 on Thursday night, reports Xinhua news agency.Lajovic, ranked 79th in the world, broke Federer first to take a 2-0 lead. But Federer broke back soon and the pair then headed to the tie-break, which Federer dominated 7-0.He kept up the pressure in the second set, bullying the 27-year-old and eventually breaking him to take a 3-1 lead.The 18-time Grand Slam champion did not look back and took the win easily."I struggled early on. I couldn't get rid of the nerves. It was a pity I couldn't hold my serve. Even though I got back into the game after that because I broke him, I just struggled in that first set," Federer said."After that I was happy to get rid of the nerves, just to play some free tennis, more inspired and at the end it was actually pretty good."Federer will next face 27th seed Mischa Zverev of Germany.Djokovic and Federer both won their opening matches after their opponents retired with an injury.Second-seeded Djokovic, who won the Wimbledon title in 2011, 2014 and 2015, is bidding to win his first Grand Slam title since the 2016 French Open."It's perfect. Exactly what I want. I don't want to have any five-set matches in there," Djokovic said.Djokovic will next face Ernests Gulbis of Latvia, who shocked Juan Martin del Potro of Argentina 6-4, 6-4, 7-6 (3).Sixth seed Milos Raonic of Germany, eighth seed Dominic Thiem of Austria, 10th seed Alexander Zverev of Germany and Spanish veteran David Ferrer also reached the third round.Among the women, third-seeded Karolina Pliskova of the Czech Republic suffered a shock defeat to Slovakia's Magdalena Rybarikova 3-6, 7-5, 6-2."That's tennis, you know. That's my case today," Pliskova saidTop-seeded Angelique Kerber of Germany advanced to the third round, along with seventh-seeded Svetlana Kuznetsova of Russia, ninth-seeded Agnieszka Radwanska of Poland and 14th-seeded Garbine Muguruza of Spain.