JOHANNESBURG -- Rory McIlroy stayed close to the leaders at the SA Open on Friday despite hurting his back.

The second-ranked McIlroy (68) made five birdies on the first six holes of the back nine but bogeyed the final two to finish in a five-way tie for fifth after two rounds.

"I'm actually surprised I'm standing here. I actually thought about pulling out before even teeing off today," he said. "I tweaked my back somehow and the first few shots today weren't very comfortable and it still isn't really comfortable. I can't really take a deep breath because I've done something to my upper back."

McIlroy said he was going to get treatment in an effort to stay in the tournament.

Graeme Storm jumped into a two-stroke lead at the top of the leaderboard after shooting a course record 9-under 63 at the Glendower Golf Club.

Storm had nine birdies and leads Peter Uihlein (64), overnight leader Trevor Fisher Jr. (68), and Jbe Kruger (67) by two.

"I tip Rory to win this week because he hits it miles and he hits it straight," said Storm, who leads at 12-under 132 overall. "If I keep on his tail, I'll be happy."

Storm finished one shy of his career best 62.

"I could have birdied a couple more of the par fives, I only birdied one of them today," he said. "So to shoot 63 and only having birdied one of the par fives around here, I've played pretty well."

Play was suspended at about 5 p.m. local time because of the threat of lightning, forcing 40 players -- including Europe Ryder Cup captain Darren Clarke -- to complete their second rounds on Saturday.

McIlroy, a stroke off the lead overnight, bogeyed the 17th when his putt for par rolled just left of the hole. He ended up in the bunker on the final hole and over-hit his escape shot. It left him with a long but straight putt for par and his attempt fell just short.

"Disappointed to finish the way I did. I thought I hit a good shot on 17, it just pitched a bit too far," McIlroy said. "Then on 18 I was probably just rushing a bit to get in before the weather. The start and the finish wasn't great but everything in between was pretty good and I'm still in contention."

McIlroy is playing this week as a favor to Ernie Els, the South African great and tournament host.