South Africa's Jacques Blaauw carded his lowest round on the European Tour to lead the weather-delayed Joburg Open at Randpark Golf Club.

Blaauw completed a second round of 63 either side of play being suspended for an hour and 50 minutes due to the threat of lightning to finish 13 under par, a shot ahead of compatriot Wilco Nienaber.

Nienaber added a 67 to his opening 63 to occupy second place, two strokes ahead of Canada’s Aaron Cockerill.

Jonathan Caldwell is the leading Irish competitor, and a round of 70 left him three under at the halfway stage.

"I’m very happy I was able to finish," Blaauw,said after carding an eagle, seven birdies and a solitary bogey.

"I hit it very well all day and then made some putts. I only made one bogey, so I’m very happy. It was very windy out there, but I found it didn’t affect my distances that much.

"I can’t think ahead because there are two more rounds to go. Golf is the job and I need to get that job done. But I’ve done some good work in the build-up to this tournament and I’m very happy with how it’s turning out.

"I’ve switched to the armlock putter and I’m very happy with it. I’m looking forward to the weekend. It’s a bit different without spectators, but I’m looking forward to it."

Nienaber held a share of the lead before play was suspended and, while Blaauw was able to pick up a birdie on the 17th on the resumption, the 20-year-old covered his last four holes in level par.

"A delay is never nice and I had it on that part of the course I really didn’t want it," Nienaber said.

"Those last four holes are really tough, but I got through it. I’m happy I finished.

"Hitting fairways here is key and I didn’t really do that today, so I had more par putts than birdie putts. I made it difficult for myself. But I’m really excited. I’ve put myself in a good position and I’m excited to see what happens on the weekend."