The 32-year-old Swede, the highest-ranked player at the tournament, made par on his first six holes before bogeying the par-four seventh to reach the turn at one over.

Stenson then had a torrid run on the back nine, carding four bogeys while picking up just one shot with a birdie on the par-four 16th.

It was in stark contrast to Derksen who put himself in a good position to challenge for a third European Tour title this weekend with five birdies against two bogeys, and is five under par overall.

“I have been playing well but not scoring well,” said the Dutchman.

“My putting has been good this week and that is key and if I can continue that into the weekend I should have a chance on Sunday.”

Local favourite Zhang, China’s most famous golfer, also enjoyed a good round in which he had a faultless run while adding three birdies.

“It has been very, very windy throughout the whole day,” said the 42-year-old.

“Before I teed off I thought that if I could finish with an even par it will be a good result because few people would be able to shoot under par in these conditions.

“I am happy with the way I played today.”

Darren Clarke was also impressive as the 2006 Ryder Cup star carded a three-under-par 69 and is one stroke behind Derksen and Zhang at four under.

“The course was very difficult with that breeze and it was difficult to get the ball close to the hole, so anything under 70 was very good,” said Clarke.

“Hopefully I can get out at the weekend and keep playing the way I know I can play.”

Overnight leader Peter O’Malley had carded a five-under-par 67 yesterday but struggled to build on that today as he completed his second round with a two-over-par 74 and is three under overall.

He is joined by Miles Tunnicliff after the Englishman carded three birdies and one bogey for a two-under-par 70.

Defending champion Raphael Jacquelin struggled once again to all-but end his chances of retaining his title after carding a two-over 74 and is three over par overall.