Luke Donald must finish in the top eight in the RBC Heritage to retain his world No 1 ranking ahead of Rory McIlroy.Luke Donald is in danger of losing his world No 1 ranking to Rory McIlroy again after opening with a disappointing four over par 75 in the RBC Heritage at a windy Harbour Town Golf Links.

The Englishman must finish in the top eight in Hilton Head to retain the number one spot he regained from McIlroy thanks to his play-off victory in last month’s Transitions Championship.

But scoring proved difficult on slick, firm greens at the South Carolina venue with Vaughan Taylor and Chad Campbell’s four under par 67s giving them an early, one-stroke lead in the clubouse from Jim Furyk, Harris Engish and Matt Every.

Donald had a poor Masters Tournament, finishing tied for 32nd behind Bubba Watson at Augusta National last week.

Yet Pádraig Harrington, who head to South Carolina in buoyant mood after finishing tied eighth in the Masters, also had a day to forget as he opened his account with a three-over par 74.

Just as it was in the final round at Augusta, the five-time Ryder Cup star was left to rue a less than brilliant day with the putter having started in the tougher, early morning conditions.

But he was also erratic from tee to gree and failed to hit the ball close enough on greens that Furyk believes have been “over-stressed” since Wednesday’s pro-am.

Harrington made life tough for himself by missing half the fairways and 10 greens. As a result he was mainly putting for pars and while he failed to do that four times, he also converted just one of his eight birdie chances.

Vaughan Taylor holed his sand wedge at the ninth for an eagle two and a share of the lead on 67.Tellingly, it was a 19 incher at the par-five fifth (his 14th) and given that he finished an average of 43 feet from the pin, it was no surprise that he averaged exactly two putts per green in regulation.      

After a solid two-putt from 70 feet at the 10th, Harrington bogeyed the 11th when he drove into the left rough and failed to chip and putt from 30 yards.

He missed the green right at the 12th and 13th, and left at the par-three 14th, but salvaged his par each time with putts of six, five and two and half feet respectively.

At the par five 15th he was again in the left rough off the tee but after hitting a good lay up to 123 yards he missed the seven footer for birdie to remain one over.

The Dubliner then missed from just inside five feet for birdie at the 16th and turned in one over 36 before coming home in a disappointing 38.

Forced to hole a six footer for par at the first after coming up short of the green with his approach, the world No 80 hit the par-five second in two blows but three-puttted from close to 60 feet/

A seven foot birdie chance slipped away that time but he then missed from just inside three feet for his par at the 200-yard fourth, having missed the green to the right.

He made his lone birdie of the day at the par-five fifth with a good chip but again failed to give himself a birdie putt at the 419-yard sixth despite going in with a wedge from just 123 yards.

He then bogeyed the 195-yard seventh, where he found a bunker left of the green and failed to make the putting surface with his recovery.

Two over for the day, he came up short of the green at the tough eighth but chipped well and holed a four a half footer for his four.

Yet there was still a sting in the tail to come at the ninth, where co-leader Taylor holed out with a sandwedge from 100 yards to claim a share of the lead later in the day.

Left with 101 yards to the flag after a perfect tee shot, Harrington flew his approach into the back bunker and again failed to make the green with his recovery.

In fact, he knocked his 21-yard par putt from the fringe some five feet past the cup and was forced to hole it for the fourth bogey of a frustrating day.