Patrick Mouratoglou craves stress. The man Serena Williams credits for taking her from "great to history," is never one to rest. The 47-year-old's pulse used to quicken when he would watch Williams, who is one of history's greatest champions and athletes. But with his pupil on maternity leave, deep into her third trimester, the coach has to now find the buzz from elsewhere. This summer marks his fifth as Williams' coach, and he has become accustomed to the attention that comes with working alongside the world's most recognizable female athlete