Serena Williams’s coach raised the prospect of the world number one skipping the remainder of the season on Tuesday as she struggles to come to terms with her failure to clinch a calendar Grand Slam. Patrick Mouratoglou told ESPN that Williams was intensely disappointed after missing out on a fifth consecutive Grand Slam crown and probably should wait until next year before returning to competition if she is not properly motivated to play. “She was two matches away from something really big, so it was very painful,” said Mouratoglou.