Jason Dufner took over at the top of the RBC Heritage leaderboard as England's Luke Donald fell off the pace during the third round at Harbour Town Golf Links.
Dufner had two eagles in a six-under par 65 to take a one-shot lead going into the final round in SC.
Dufner, the 2013 PGA Championship victor, collected eagles on the par-five second and fifth holes, then struck for birdies at the 14th through 16th holes for a round of 6-under 65 at Harbour Town Golf Links on Hilton Head Island.
"It was a little bit of a roller coaster but it was good to pick up a couple of eagles", Dufner told the PGA Tour website.
"I really got it going on the back nine (with four birdies in a row, including three in a row through No. 16), and that bodes well for (Sunday)".
"It was disappointing to finish with a bogey on the last hole, but obviously I've been playing well and I'm excited about (Sunday)", said DeLaet, who has won three times on the PGA Tour Canada but has never won in 159 prior PGA Tour starts.
Poulter proceeded to double bogey the hole and bogey the next, but a birdie on the 14th helped him card a two-under 69 and move to 10 under, a shot ahead of compatriot Donald.
Webb Simpson, who clinched the US Open back in 2012, and fellow American Kevin Kisner are in a two-way share of third on -11 after signing for rounds of 68 and 66 respectively.
With play completed, Dufner leads 36-hole co-leader Graham DeLaet by one shot.
A large alligator was lurking by the water's edge and left Poulter reluctant to play his shot, fearing the reptile could snatch his club or even come for him!