Rory McIlroy made a mess of his start and his finish but played some stunning golf in between to card a disappointing 68 in a weather-hit second round at the European Tour's South African Open.

The world number two is nine under par for the tournament, three shots behind clubhouse leader Graeme Storm after the Englishman carded a course-record equalling nine under-par 63 to grab the outright advantage at the halfway stage of the world's second oldest national open championship.

Play was suspended late in the day due to the threat of lightning with 40 players still to complete their second round, which will resume at 0515 GMT on Saturday morning.

American Peter Uihlein (64), and South Africans Jbe Kruger (67) and Trevor Fisher Junior (68), are all two shots off the lead at 10 under-par.

It was McIlroy's mixed round, however, that had the spectators enthralled.

"Overall, the start and the finish wasn't great but everything in between was pretty good."

After a bogey on the second hole, he clawed a shot back with a birdie on the third, before double-bogeying the par-four fourth.

An eagle on the par-five eighth then sparked a run of six birdies in the next seven holes.

The Northern Irishman, however, lost concentration and bogeyed the 17th and 18th, which have played as two of the easier holes in the tournament so far.

"Once I got it going and saw putts going in I got some momentum which was nice," he told reporters.

"Disappointed to finish the way I did. I thought I hit a good shot on 17, it just pitched a bit too far. Then, on 18, I was probably just rushing a bit to get in before the weather.

"Overall, the start and the finish wasn't great but everything in between was pretty good."

Storm started with three consecutive birdies and added a further six more in a brilliant round.

"It's obviously great to shoot a score like that," he told reporters. "I had a putt on the last, it was a long putt to equal my best-ever score.

"I tip Rory to win this week because he hits it miles and he hits it straight. If I keep on his tail, I'll be happy."

Home golfer Jaco van Zyl carded a 65 that included a hole-in-one on the par-three 17th.