Rory McIlroy today began his bid to become the youngest Open champion since 1893, but it was veterans Mark Calcavecchia and Thomas Bjorn who were making the early headlines.

McIlroy came into the 140th Open Championship at Royal St George's as favourite following his record-breaking US Open victory at Congressional last month, since when he has not played competitively.

And the 22-year-old perhaps showed signs of a little rustiness when he bogeyed the opening hole, three-putting from just over the green after playing partner Rickie Fowler had holed out for birdie from an almost identical position.

Play had started on schedule at 6:30am, with 1989 champion Calcavecchia in the second group out and picking up birdies at the fourth and seventh.

The 51-year-old American reached the turn in 33 and was joined at the top of the leaderboard by 41-year-old Bjorn, who was famously joint second when the Open was last staged here in 2003, blowing a three-shot lead with four holes to play after taking three shots to escape from a greenside bunker on the 16th.

He was only sixth reserve as recently as last week before a spate of withdrawals, but was making the most of his call-up on Monday when Vijay Singh pulled out through injury.

After saving par from over the green on the downwind first, Bjorn holed from 14 feet for a birdie on the second and almost repeated the trick from twice the distance on the third.

The former Ryder Cup player then saved par on the next two holes with good chips to three and six feet respectively, missed from eight feet for birdie on the sixth but holed from five feet for birdie on the par-five seventh.

Players had been struggling to even reach the seventh fairway in the strong winds on Tuesday and Wednesday, with tournament officials admitting tees would have to be moved forward if similar conditions persisted.

And that was indeed the case today on the par-three 11th, where Phil Mickelson and Luke Donald had both been unable to reach the green with a driver on Tuesday.