Rory McIlroy off to confident start after long storm delay at BMW Championship

Rory McIlroy continued his excellent recent form with a confident start to storm-interrupted opening day of the BMW Championship in Indiana.

McIlroy reached three under par for the 10 holes he completed before darkness fell as torrential rain and the threat of lightning caused a three-and-a-half hour suspension earlier in the day.

Roberto Castro set the early clubhouse target after a superb seven-under 65 blighted only by a bogey at the last, and the American holds a one-shot advantage over Brian Harman with Dustin Johnson well placed after 67.

Castro cruised to the turn in 33 and then reeled off five birdies in seven holes from the 11th, including a sublime chip-in for a rare three at the tough 14th, but he needed three to get down from the fringe at the 18th.

Harman's 66 was blemish-free as he rolled in four birdies in seven holes around the turn and then knocked a long second to 15 feet at the long 15th and rattled in the putt for eagle.

Jason Dufner birdied three of the last four holes to return a 67, while a change of putter worked wonders for Johnson as he surged to six under when he nailed his seventh birdie of the day at 15.

But with the light fading, the US Open champion appeared to rush his drive at the last and carved his ball into the water, although he did well to hammer his third to the fringe of the green and limit the damage to a bogey.

Chris Kirk, playing in the last group out, stormed to the turn in five under and has yet to begin his back nine, while Adam Scott also enjoyed an outward 31 which he capped with an eagle at the ninth, only to give one back when he missed a par putt of barely two feet at the next.

Paul Casey, runner-up to McIlroy at last week's Deutsche Bank Championship, matched Scott's eagle at nine and is nicely placed on four under with eight holes remaining, while Ryder Cup star Sergio Garcia was another to cash in at the ninth - his eagle-three being the highlight of a solid, three-under 68.

McIlroy's renewed confidence with the putter was again evident at the first, where he converted from 12 feet for an opening birdie, and he followed a good up-and-down at the fifth with a delightful tee-shot to five feet at the next as he moved smoothly to three under.

The world No 3 took a step back when he raced a lengthy birdie putt seven feet past the target at the seventh and the return lipped out, but he responded with an easy four at the ninth and had just parred the 10th before the klaxons sounded.

McIlroy's playing partner Jordan Spieth is a shot further adrift along with current FedExCup leader Patrick Reed, but world No 1 Jason Day failed to take advantage of the favourable scoring conditions as he struggled to a 73.

Day, who saw the funny side of being mistakenly introduced as "Jordan Day" on the first tee, mixed five birdies with six bogeys in another inconsistent showing, while Olympic champion Justin Rose faces a huge task to make the Tour Championship after slipping to three over par with two holes to play.

CHANNEL CHANGE: Day two coverage of the BMW Championship will now start at 2pm on Friday on Sky Sports 3.