Rafael Nadal defeated big-serving Karen Khachanov in straight sets to reach the fourth round at Wimbledon here on Friday.The 10-time French Open champion fired 41 winners to beat the Russian 6-1, 6-4, 7-6 (3) on Centre Court to move into the last 16 for the first time since 2014, Xinhua news agency reported"For a while I played fantastic, in the first set and a half, it was a great level," Nadal said. "Then it was a little bit tougher."Nadal reduced the powerful 21-year-old to a mere bystander in the first 30 minutes of the match, moving energetically on the grass on a sweltering late afternoon.It took Khachanov, ranked number 34 in the world, half an hour to get a service hold on the board, in the first game of the second set.The Russian managed to find his form in the third set, forcing it into a tie-break but made three unforced errors to see the chance slip off his hand."I played some good shots, from the forehand and the backhand," said Nadal. "Happy with almost everything. But in the third, I started to play a little bit shorter."Since losing the 2011 final to Novak Djokovic, Nadal has been knocked out before the quarterfinals for four straight years by a player ranked outside of the top 100. He missed Wimbledon last year with a wrist injury.