A resurgent Ross McGowan carded a sparkling 62 to claim the halfway lead in the Joburg Open as he looks to claim an overdue second European Tour title.
McGowan fired six birdies, two eagles and just one bogey on the West Course at Royal Johannesburg & Kensington Golf Club to finish 14 under par, three shots ahead of the chasing pack.
After reaching the turn in 33, McGowan birdied the 10th and holed his second shot to the 12th for an eagle, before picking up another birdie on the 14th and holing from 15 feet for eagle on the par-five 15th to cover the back nine in 29.
The 33-year-old won the Madrid Masters in 2009, aided by a career-best 60 in the third round, but lost his card in 2011 before regaining it last November by finishing fifth in the qualifying school in Spain.
"I played well yesterday and started well today, opening up with two birdies," said McGowan, who was in contention in last week's BMW SA Open before a closing 74 dropped him into a tie for 12th.
"It went a bit flat for a few holes, then on the back nine the fireworks started. I holed a wedge on 12, which was nice, and hit two great shots into the par five and had 15 or 20 feet for eagle -- and holed that as well."
Chile's Felipe Aguilar had matched McGowan's 67 in the opening round and added a flawless 65 on Friday to share second place on 11 under with England's Anthony Wall and South African pair Haydn Porteous and Jean Hugo.
Aguilar has not played competitively since the end of November and revealed he had prepared for his 2016 debut by completing an iron-man triathlon.
"I feel very comfortable, very healthy, which is the only thing I was hoping for this week," the 41-year-old said. "I had to take some measures as soon as I finished [the triathlon], like an IV, trying to hydrate again, a pool of ice, things like that.
"I had to do everything the way they wanted actually and it worked out pretty good. Even though I had that race last week I was practising pretty much every day early in the morning and I was doing the iron-man training in the afternoon, but it was awesome.
"Golf is a lot easier health-wise than the triathlon. That was something really extreme for me, it was an amazing experience, but it takes a little bit too much time from golf, so I'll put that aside and I'm going to wait a couple more years until I do another one."
Wall finished joint second in this event last year and finished his 67 in style with an eagle at the 18th as he looks to add to his sole European Tour victory to date, which also came in Johannesburg in 2000.
"I've had six weeks off with a really bad neck and I'm sort of so-so now, so my practice was pretty average while I was at home, it was pretty sparse," Wall said.
"Normally I work pretty hard in the off-season so I was rusty, but my method is there. To get to 11 under on two good tracks, I think my first week has been great. I'm really looking forward to a good weekend."
Welshman Stuart Manley and Sweden's Johan Carlsson were four shots off the pace on 10 under, with Ireland's Paul Dunne, who shared the lead after 54 holes of the Open last summer as an amateur, a shot further back after a flawless 63 on the West Course.
Four-time major winner Ernie Els, who accepted a late invitation into the event, birdied the 18th on the East Course to make the halfway cut on the mark of three under.