Henrik Stenson will go into the final round of the Memorial Tournament five shots behind Spencer Levin after a third round 71.
The Swede reached five under for the week on the front nine but three bogeys after the turn dropped him back to three under and a share of fifth place.
American Levin carded an impressive 69 to lead Rory Sabbatini by one, with Rickie Fowler three off the pace on five under.
Tiger Woods is a shot further back in solo fourth after a 73, with Vijay Singh and Andres Romero also in the top ten.
World Number One Luke Donald had a disappointing 75 to slip to 36, but Race to Dubai leader Justin Rose managed a 71 to move into the top 20.