The children of the late Robin Williams celebrated their father's memory with the help of his close friend Billy Crystal in touching scenes at the AT&T Park on Sunday night. Prior to the start of the San Francisco Giants/Kansas City Royals World Series Game at the venue, Zak Williams, oldest son of the hugely popular comedian, fielded the ceremonial first pitch to Crystal. Zach was joined at the mound by his sister Zelda and brother Cody for the event When Crystal caught the pitch, the stadium erupted and Zach made his was to his late father's close friend for an emotional embrace. In a further nod to the actor, who was a huge San Francisco Giants fan, a tribute played on the main centre-field scoreboard featuring snippets from many of his beloved movies and pictures from his days at the games. In a statement released through the Giants, the Williams children said: "We are honored to be here in support of the tribute to our father, someone who loved his hometown and especially the Giants."   "For all of us, it is a tremendous delight and a little surreal to throw out the ceremonial first pitch of a World Series game for our team to our dad's best friend. We could not think of a better way to celebrate his memory. Let's go Giants!" Williams was 63 when he passed away on August 11th.