Golf-Watson shoots 63 for two-shot lead at World Challenge

* Eagle at par-four fourth sets tone * Casey also cards 63 * Spieth slips four behind (Adds details, quotes) Dec 5 (Reuters) - American Bubba Watson carded a flawless course record-equalling nine-under-par 63 and stormed to a two-stroke lead over Englishman Paul Casey after the third round at the Hero World Challenge in the Bahamas on Saturday. The dual Masters champion, boosted by an early eagle, added seven birdies to post a 19-under 197 total at Albany Golf Club in New Providence. Watson was caught by surprise by his eagle, with a seven-iron from 169 yards at the par-four fourth. He yelled at his ball to get "down" as it flew through the air, and it obeyed nicely, landing some 18 inches in front of the cup and bouncing in. In the field as an alternate after Australian Jason Day withdrew, Watson is in prime position to win, though his record in closing the deal is not exactly comparable with tournament host Tiger Woods. Watson has won only twice out of nine times on the PGA Tour when holding the lead or a share of the lead through 54 holes, while the third round leader has won the World Challenge only three times in the last 11 seasons. "It was a good day," Watson told reporters. "The key for me around this golf course, I think for everybody, though, as we're seeing, when there's no wind, light wind, we can score. "We're all good players, don't get me wrong. We're all top 50 in the world. But with no wind, this golf course is a little bit easier to make birdies." Second-placed Casey, who earlier set the record mark with a 63 of his own, moved into second place on 17-under, with Americans Patrick Reed and Chris Kirk another shot behind. World number one Jordan Spieth, who held a share of the halfway lead, carded 68 to slip four shots behind. With birdies a plenty on offer in ideal conditions, Jimmy Walker, another 36-hole co-leader, shot 71 to drop seven shots off the pace. The $3.5 million tournament, which comprises an exclusive 18-man field, offers world ranking points, though it is not an official PGA Tour event. (Reporting by Ben Everill in Los Angeles; Editing by Andrew Both)