Novak Djokovic approached his relatively unknown opponent, the world’s No. 204 player, with a smile. He had just suffered one of the most shocking losses of his career, falling to to Valentin Vacherot in the semifinals of the Shanghai Masters, yet the tennis icon wanted to give his foe his proper credit. “You deserve it,” Djokovic said. “You played unbelievable. … Keep going.” With the 38-year-old Djokovic’s career winding down, Saturday morning’s result marked one of the wildest upsets he’s