Those who have followed Cobolli's rise over the past 12 months will not be surprised to see him making a maiden appearance in the last eight of a Grand Slam. He won his first ATP Tour title this year in Romania and followed that up with victory in Hamburg. Until facing Cilic, he had not dropped a set at SW19 and has secured comprehensive victories in all four of his matches. But against Djokovic the challenge is far more daunting. And the 24-time Grand Slam champion has been doing some analysing of his own. The 36-year-old said his son has been asking players at the All England Club to sign his hat and even managed to hit with Cobolli. "They hit a few days ago. They played some points," said Djokovic. "He's over the moon. Obviously, he loves tennis. He has everyone's signature, except mine. But that's okay, I'll accept that. "I'll have a conversation with my son and see what he has noticed in the game of Cobolli." On the court, Cobolli's varied shot selection and athletic movement has entertained the Wimbledon crowds. But Djokovic said he has been surprised to see Cobolli's results on grass, with his game not necessarily suited to the surface. "He's a very talented player," he said. "One of the youngsters coming up. He's a big fighter. We get along well. We practise whenever we can. "Let the better player win. What can I say?"