Luke Donald's quest to regain the World Number One position from Rory McIlroy remains on course after the third round of the Zurich Classic of New Orleans.

The 34 year old needs a top seven finish at Avondale to take over at the top of the rankings - and he moved up to eighth with a third round 66, sharing that placing with Ken Duke.

Donald produced birdies at the second, fifth, seventh, tenth, 13th, 14th and 18th holes, with the only blemish on his card a bogey at the par four sixth.

It moves him to within five shots of leader Jason Dufner, who shot five under par in his third round to take a two stroke lead over Graham DeLaet.

Dufner has not won in 163 starts on the US PGA Tour and is best remembered for losing a play-off to Keegan Bradley in last year's US PGA Championship.

However, he followed rounds of 67 and 65 with another 67 to maintain control of this tournament in Louisiana.

DeLaet shot a 66, while a further stroke back were John Rollins and Ernie Els, who shot 69 and 68 respectively.

Ryan Palmer tied the course record with a 64 to join Steve Stricker and Cameron Tringale at 13 under.