DUBLIN, June 7: South African Ernie Els boosted his confidence ahead of the US Open in two weeks' time by romping to a four-shot victory at the $5.25 million Memorial Tournament at Muirfield Village on Sunday.

The world number three, ahead by two strokes after the third round, briefly lost the lead after a bogey at the fourth. But he was four-under-par over the next six holes and eventually finished with a six-under 66 for an 18-under tally of 270.

Fred Couples, the 1998 champion here, was in second place after hitting a 68 for 274. World number one Tiger Woods carded his third consecutive round in the 60s, a three-under 69 giving him third place on 276.

Britain's Justin Rose was fourth on 277, one stroke ahead of South Korean K.J. Choi. Defending champion Kenny Perry and Stephen Ames of Trinidad and Tobago finished joint sixth on 279.

Tournament host Jack Nicklaus, 64, returned a closing 71 to finish in a tie for 63rd place on 295, seven over. After Els bogeyed the fourth, Couples chipped in from 25 feet to briefly take the lead. But the South African hit back immediately with a birdie at the fifth.

Woods was 12-under through seven before parring each of the last 11 holes. The world number one drove the ball as well as he has done all year for the first 10 holes but then missed three fairways in a row in the middle of the back nine.

Leading final round scores: