Robert-Jan Derksen and Jean-Francois Lucquin share lead

The two players had to return to the course to finish their storm-interrupted first rounds before establishing a three-shot lead on nine-under-par 131 when darkness ended play prematurely in the second round.

Half the field must return on Saturday morning to complete their rounds.

Derksen followed up a 66 with a 65 in the final counting event for this year's European order of merit to lift his chances of claiming the third win of his career.

The 33-year-old, lying 42nd on the money-list, was disappointed to three-putt twice but happy he had come through a grueling day.

"We used to play 36 holes as amateurs with no problem but it seems when you get to the pro level it's a lot harder," Derksen told Reuters.

"It would be nice to get close to a top-20 spot (this week) because a lot goes with it including (a place in) the British Open."

While Derksen is assured of a spot in next week's Volvo Masters at Valderrama, the 88th-placed Lucquin needs to finish in the top two here to qualify.

The 28-year-old Frenchman, like Derksen, played 31 holes in the day.

Lucquin said his rounds of 66 and 65 were down to a new coach.

"One and a half months ago I changed my coach to Richard Gillot, who used to play with me on the Challenge Tour and is my son's godfather," he said.

"He knows my game and last week in Portugal everything started to take shape. I finished with a 64 there and felt I could carry it on to this week."

The pair lead by three shots from Ireland's Peter Lawrie and Dane Mads Vibe-Hastrup, who won the Madrid Open two weeks ago, and by four from Swede Niclas Fasth, Thai Thongchai Jaidee and Briton Sam Little.

Title favorite Sergio Garcia was three under par after 27 holes.