Every player's first MLB home run is a moment to cherish. But, when it's a grand slam? That's extra special. San Francisco Giants second baseman Christian Koss did just that against the Arizona Diamondbacks, erasing a 3-0 deficit with the second-inning blast. His grand roundtripper propelled the Giants to a 10-6 win. "I kind of blacked out a little bit," Koss later said.