|RBC Heritage third-round leaderboard|
|-14: T Merritt (US); -11: B Todd (US), K Kisner (US), M Kuchar (US); -10: B Garnett (US), B Grace (Rsa), J Furyk (US); -9: B Van Pelt (US), J Spieth (US)|
|Selected others: -8: L Donald (Eng), G McDowell (NI); -7: I Poulter (Eng), R Knox (Sco); -1: M Laird (Sco)|
Masters champion Jordan Spieth is five shots behind leader Troy Merritt going into the final day of the RBC Heritage.
Spieth, 21, carded a three-under-par 68 in the third round in South Carolina to reduce the gap between him and fellow American Merritt, 29, by one shot.
Merritt, on 14 under, leads by three shots from compatriots Brendon Todd, Kevin Kisner and Matt Kuchar.
England's Luke Donald and Northern Ireland's Graeme McDowell are six shots off the lead, in a tie for 10th place.
McDowell, who led after carding 66 on day one, has slipped down the field after following up his second round score of 69 with a 70. That has left him level with Donald, who shot a five-under 66 on Saturday.
Englishman Ian Poulter is one shot further back on seven under, level with Scotland's Russell Knox, after both shot rounds of 67.
Spieth had made a poor start to the tournament following his Masters win in Augusta last Sunday as he struggled to a three-over-par first-round score of 74, but moved to six under on a bogey-free second day.
His third-round 68 was the American's 18th sub-par round in his last 19 and he said of his prospects of victory: "There's a low one out there and I think it's certainly possible."
Tournament organisers have announced players will play from two tees on Sunday and tee off between 07:30 and 09:30 local time because of a threat of bad weather.