Henrik Stenson, winner of the Players Championship in Florida two weeks ago and the event’s top-ranked player at fourth in the world, was in even worse trouble.

After bogeying the first the Swede matched McIlroy’s six two holes later to slump to three over, four behind the five early pacesetters – English trio Anthony Wall, Robert Rock and David Horsey and Swedes Peter Hanson and Alexander Noren.

South Africans Ernie Els and Retief Goosen also bogeyed the first – and so did Colin Montgomerie.

Europe’s Ryder Cup captain used to consider himself one-up on the first tee of the West Course because he knew it so well and had such a good record – he won the title three times in a row from 1998 – but he was relieved not to kick off the £4million with a double bogey.

After pulling his drive, his approach found the bunker short of the green and from there he only just got out and had to chip close to rescue a five.

Rock had the day’s first birdie on the 473-yard opener, a massive drive rolling down the slope and leaving him only a short-iron second.

The 32-year-old is trying again for a first European Tour win four days after losing a play-off for the Irish Open to amateur Shane Lowry.

Rock had a nine-foot putt on the first extra hole to triumph at County Louth, but his bogey six two holes later led to wild scenes.

Lowry is not at Wentworth, but was expected to announce his decision to turn professional at a Dublin hotel this afternoon.