Sweden's Carl Pettersson had a bogey-birdie-par finish to complete his rain-hit third round at the Memorial tournament, stretching his lead to two shots.
Pettersson had held a one stroke advantage on Woody Austin and Zach Johnson overnight but the two Americans both bogeyed the last to slip down the leaderboard.
The Swede, who claimed his only PGA Tour win last year at the Chrysler championship, arrived at the Muirfield Village Golf Club with three holes to play and signed for three-under 69 to move to 11-under 205 for the tournament.
Austin (67) lurks two back on nine-under 207 with Johnson (70) one shot further adrift at 208 after stumbling to the finish with bogeys at 17 and 18.
World number two Phil Mickelson, who had one hole to complete when play was halted on Saturday due to darkness and inclement weather, also faltered with a bogey at 18 to return a two-under 70 and fall four shots off the pace.
