Novak Djokovic said he felt overwhelmed at the news he will now be the only active member of the so-called ‘big four’. With Roger Federer and Andy Murray having already left the sport, Rafael Nadal announced on Thursday that he will also hang up his racket at the end of the season. Djokovic has spent nearly two decades battling his biggest rivals, having recorded the most grand slams of them all, 24, compared to Nadal’s 22, Federer’s 18 and Murray’s three