|Hero World Challenge round one leaderboard|
|-6 J Walker (US), Z Johnson (US), P Casey (Eng); -5 A Scott (Aus), B Watson (US), B Haas (US), J Spieth (US), B Koepka (US)|
|Selected others:-4 D Johnson (US), -2 R Fowler (US), -1 J Rose (Eng)|
England's Paul Casey shot a six-under-par 66 to share the lead after round one of the Hero World Challenge.
Casey's bogey-free round put him top of the leaderboard alongside American pair Jimmy Walker and Zach Johnson at the event hosted by Tiger Woods.
World number one Jordan Spieth sunk a hole-in-one on the par-three second, but finished a shot behind the leaders.
The US Open and Masters champion, who used a six-iron from 172 yards for his ace, also carded a bogey-free round.
The Hero World Challenge, which is taking place at Albany in the Bahamas, features 18 of the top-ranked golfers in the world.