Castro leads by one at weather-hit BMW (Reuters)

View photosMoreSep 8, 2016; Carmel, IN, USA; Roberto Castro lines up a putt on the 18th hole during the first round of the BMW Championship at Crooked Stick GC. Mandatory Credit: Brian Spurlock-USA TODAY Sports(Reuters) - Roberto Castro upstaged some of the biggest names in golf to take a one-shot lead at the rain-hit BMW Championship on Thursday with a seven-under-par 65, while defending champ Jason Day ended the day eight strokes back after a six bogey 73.

FedEx Cup points leader Patrick Reed managed a respectable two-under 70 while Rory McIlroy, winner of the Deutsche Bank Championship on Monday, was three-under after 10 holes.

Castro reeled off eight birdies before missing a six-foot par…