<p>Novak Djokovic moved within four matches of completing the first men's singles calendar-year Grand Slam in 52 years on Saturday, rallying to beat Japan's Kei Nishikori at the US Open.</p>.<p>Top-ranked Djokovic improved to 18-2 overall against Nishikori, taking his 17th consecutive victory in the rivalry by 6-7 (4/7), 6-3, 6-3, 6-2 at Arthur Ashe Stadium.</p>.<p>The 34-year-old Serbian star advanced to a fourth-round matchup Monday against either 99th-ranked US wildcard Jenson Brooksby or Russian 21st seed Aslan Karatsev.</p>.<p>With a fourth career US Open trophy, Djokovic would complete the first men's singles sweep of major titles in the same year since Rod Laver in 1969.</p>
<p>Novak Djokovic moved within four matches of completing the first men's singles calendar-year Grand Slam in 52 years on Saturday, rallying to beat Japan's Kei Nishikori at the US Open.</p>.<p>Top-ranked Djokovic improved to 18-2 overall against Nishikori, taking his 17th consecutive victory in the rivalry by 6-7 (4/7), 6-3, 6-3, 6-2 at Arthur Ashe Stadium.</p>.<p>The 34-year-old Serbian star advanced to a fourth-round matchup Monday against either 99th-ranked US wildcard Jenson Brooksby or Russian 21st seed Aslan Karatsev.</p>.<p>With a fourth career US Open trophy, Djokovic would complete the first men's singles sweep of major titles in the same year since Rod Laver in 1969.</p>