Paul Dunne fired a bogey-free round of 63 to move to nine under at the halfway stage of the Joburg Open.
After shooting a 71 on day one, Dunne, playing in his eighth professional event, carded eight birdies in his bogey-free round at the West Course at Royal Johannesburg and Kensington and is currently five shots behind clubhouse leader Ross McGowan.
The latter hit a sparkling round of 62 that included six birdies, two eagles and just one bogey on the West Course to finish 14 under par, three shots ahead of Felipe Aguilar, Anthony Wall and Haydb Porteous.
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 12 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.
Aguilar had matched McGowan's 67 in the opening round and also went to the turn in 33 before picking up shots on the 11th, 15th and 17th to complete a flawless 65.
Wall, whose sole European Tour title to date also came in Johannesburg in 2000, finished his round in style with an eagle on the 18th to card a 67
Every now and then my putter behaves itself! Nice days work. #scottycameron— Paul Dunne (@dunners11) January 15, 2016
First-round leader Justin Walters delivered a round of 69 to join Dunne at the nine under mark.
Of the other Irish competitors, Kevin Phelan and Michael Hoey finished on the cut mark of three under after rounds of 72 and 69 respectively. However, Ruaidhri McGee's will not be around for the weekend after a 76 saw him finish at four over.
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 after a consecutive round of 70.