Joint first-round leader Paul Dunne has dropped down the field at the Alfred Dunhill Championship after a one-over-par round of 73.
The Greystones man was tied with Charl Schwartzel overnight but four bogeys and three birdies on round two left him in a tie for 19th in Malelane, South Africa.
Michael Hoey also slipped back after a 71 to sit at four under, while Darren Clarke and Jack Hume missed the cut after shooting rounds of nine and four over par respectively.
Brandon Stone is looking forward to doing battle with defending champion Schwartzel this weekend after firing an eagle at the last to lead by a single shot.
.@BrandonMStone with an eagle putt on 18 to take the lead....#DunhillChamps https://t.co/fkpO4PAX0a
— The European Tour (@EuropeanTour) December 2, 2016
After mixing six birdies with two bogeys in his first 17 holes on Friday, Stone coolly slotted in his 10-foot eagle putt at the last to move to 11 under par.
The 23-year-old is one stroke clear of Schwartzel - a four-time winner of this event - and Englishman Chris Hanson, with home favourites George Coetzee and Keith Horne another shot back on nine under.
Stone, who was struggling with a back injury during his second round, told www.europeantour.com: "He (Schwartzel) seems to like this place so hopefully we get drawn together tomorrow and hopefully we can have a good weekend of competition against each other.
"I woke up this morning and the back was feeling a little bit sore, and then on the range it didn't really feel too great either.
"During the course of the day it progressively got worse and then I had to hit one out of the deep jungle on the right of number eight and really tweaked it.
"I got some really good physio with my trainer on the ninth. I got the back sorted for a few holes there and it held its nerve for the back nine."
Hanson, meanwhile, carded eight birdies and a single bogey in his second-round 65 to climb up to joint second.
