By Patrick Johnston SINGAPORE (Reuters) - Jordan Spieth may be sitting proudly at the top of the world rankings but the American believes his short game needs plenty of work before he can regain the mantle of the hottest player in golf. The 22-year-old double major winner finished tied for fifth at the European Tour's Abu Dhabi Championship on Sunday after some erratic play on the greens left him five shots adrift of compatriot and champion Rickie Fowler. The victory in a strong field also featuring four-times major winner Rory McIlroy and world number six Henrik Stenson left Spieth, already a winner in Hawaii this year, with someone to target. More...