LONDON—It was business as usual for top seed Novak Djokovic as the Serbian dismantled the challenge of Chile’s Cristian Garin with a 6–2 6–4 6–2 victory to reach the last eight at Wimbledon and keep his title defense intact at the grasscourt major. The world No.1, who won the last two men’s singles titles at the All England Club, will play his 50th Grand Slam quarter-final when he faces unseeded Hungarian Marton Fucsovics, who ousted Russian fifth seed Andrey Rublev 6–3 4–6 4–6 6–0 6–3. Only the 39-year-old Roger Federer, an eight-time winner at Wimbledon, has reached more Grand Slam quarter-finals. The 25-year-old Garin, seeded 17th, had never played Djokovic on grass before and soon realized he did not have the resources to trouble the Serbian on a sun-baked Centre Court. Djokovic won the first eight points and never took his foot off the pedal during the one hour 48 …