Chris Kirk and Billy Horschel are tied atop the leaderboard after the first round of the TOUR Championship.  Both carded a four-under 66 on Thursday at East Lake Golf Club to lead a pack of four golfers by one shot.  Patrick Reed, Jason Day, Jim Furyk [[ FURE-ick ]] and Bubba Watson are all at minus-three.  Rory McIlroy and Sergio Garcia both opened with a one-under 69.  Kirk is currently number-one on the FedExCup points list after winning the Deutsche Bank Championship two weeks ago.  Horschel is coming off a win at last week's BMW Championship and is second on the points list.  Any of the current top-five players on the points list would claim the FedExCup title with a win this week, while anyone outside the top five will need a win and some help.