Billy Horschel retained his two-shot lead going into the final round of the Valero Texas Open in San Antonio.
The in-form Floridian recorded five birdies to go with three bogeys as he added a round 70 to his earlier pair of 68s.
The 26-year-old looked solid for the entire third round and is in a good position to go one better than last week, when he tied for second in Houston.
Jim Furyk shot a 69 to join Charley Hoffman (70) on eight under par to be two back, while there was a further two-shot break back to a group of three players that include Rory McIlroy.
The Northern Irishman started the round three off the lead and began brightly with birdies at the first and third.
However, he gave one back at the next and the momentum was lost with successive dropped shots at the 10th and 11th in a round in which he was erratic from the tee.
But he remained in touch with the leaders with two birdies in the next three holes and sits alongside Texan duo Ryan Palmer (68) and Bob Estes (69).
Ireland's Padraig Harrington and Scotland's Martin Laird are a further stroke behind after rounds of 70, while David Lynn was the highest-placed Englishman in the field on three under overall after a third-round 71.