Day carries old back, new caddie to first-round 64 at BMW

FILE PHOTO - Aug 26, 2017; Old Westbury, NY, USA; Jason Day hits his second shot on the tenth hole during the third round of The Northern Trust golf tournament at Glen Oaks Club. Mandatory Credit: Dennis Schneidler-USA TODAY Sports

(Reuters) - Jason Day had a new caddie to carry his clubs but was stuck with the same old troublesome back in the opening round of the BMW Championship on Thursday.

Walking gingerly between shots at Conway Farms outside Chicago, the former world number one nevertheless swung with apparent freedom to card a seven-under-par 64 and end the day two strokes behind compatriot Marc Leishman in share of second.