World No. 1 Carlos Alcaraz split with longtime coach Juan Carlos Ferrero took the tennis world by surprise. Neither of them has been too forthcoming on the reasons for the separation – even though the older man had hinted at some contract issues – but in his first comments on the separation, the 22-year-old described the development as “a chapter of life that has to end.” Ferrero, himself a former top-ranked player in the world and a Grand Slam champion, had guided Alcaraz since he was 15, and played a pivotal role in him winning six major titles. There was speculation that the former French Open champion didn’t want to end the relationship, but Alcaraz said on Friday that “closed this chapter in mutual” last month. The Spaniard is in Melbourne for the Australian Open, which starts on Sunday, where he will try to complete a career Grand Slam, becoming the youngest man in history to accomplish the feat. “We both are still friends, good relationship. But we just decided like this. I’m really grateful …