Sweden's Alex Noren is in pole position to claim a fourth European Tour title of the season after the weather-affected second day of the Nedbank Golf Challenge.

Noren carded a second round of 67 at Sun City to reach the halfway stage of the on eight under par, two shots clear of England's Chris Wood, Paraguay's Fabrizio Zanotti and home favourites George Coetzee, Louis Oosthuizen and Jaco van Zyl.

Victory on Sunday could take Noren to within 500,000 points of Race to Dubai leader and fellow Swede Henrik Stenson, who is seven shots off the pace after struggling to a 74.

And it would also take the 34-year-old into the world’s top 10 for the first time, having been ranked 110th in May before winning the Scottish Open, European Masters and British Masters.

Zanotti had earlier recorded the first hole-in-one in the tournament’s 35-year history, following birdies at the first and second by holing out from 210 yards with a seven iron on the fourth.

“It was a great start, I couldn’t believe it,” Zanotti, who bogeyed the last two holes in his 68, told Sky Sports. “It sounded strange when the tournament people told me I was the first to do it, but lucky for me that I’m the first one.

“I fought hard all day long and I’m in a very good position for the weekend.”

Oosthuizen’s flawless 66 was the lowest score of a second round delayed by an hour and 42 minutes due to the threat of lightning, which meant play ended in near-darkness.

“I felt like I hit the ball really well on Thursday but couldn’t keep bogeys off my card and it was great to finish level after all that and then sort of build on the momentum going into today,” the former British Open champion said. “I feel good over the ball and just need to make a few putts.

“I’ve won the Dimension Data here before, I love this place and it’s great playing on a great golf course. There’s a lot of holes where you think you can overpower it by just bombing a driver but I took the hard route today, a few three irons and a lot of five woods off the tee to give myself a mid-iron into the green.”

Stenson had started the day just a shot off the lead, but the British Open champion carded a hat-trick of bogeys from the third and also double-bogeyed the 14th before repairing some of the damage with birdies on the 16th and 18th.

The 40-year-old can end the season as European number one for the second time in four years with a victory this week, providing his nearest rival Danny Willett finishes outside the top 10.

Masters champion Willett has struggled for form recently but looked like improving on his opening 75 when birdies on the seventh and eighth took him to the turn in 35.

However, Willett then carded a double bogey on the 13th and dropped another shot on the next on his way to a second round of 74 to occupy a share of 54th place on five over.

Noren, who carded six birdies and a solitary bogey, said: “I made a lot of birdies on the back nine after that rain delay, which was great fun. I holed a chip, it was a good nine.

“I’m very pleased how I kept it together, because it is a tough golf course. A little bit of a wayward shot and you can be in some difficult positions.

“I know how tricky this game is and I’m just trying to improve every day, every week.”

Pádraig Harrington carded a three-over 75 to slip back to seven over in the no-cut event.

Harrington did eagle the par-five ninth a day after carding an ugly double-bogey seven on the 545-yard hole.

That helped Harrington make the turn in two under after a birdie on the second and a bogey on the fourth, but he faltered on the back nine, carding five bogeys in seven holes from the 11th.