Defending champion Louis Oosthuizen took a single shot lead after the third round of the European Tour’s South African Open on Saturday following a birdie rush in his first few holes. Oosthuizen dropped just one shot after 54 holes at the Randpark Golf Club and carded another seven birdies during his round of 64 to move to 15 under-par for the tournament as he aims to register back-to-back wins in his home championship. He has been winless on tour since clinching this trophy in December 2018 when he beat Romain Langasque by six strokes. "Getting my name on the trophy again would really mean the world to me," Oosthuizen told the European Tour website. "Defending it and being the host for the week would make it extra special. "It was good, it was solid. I gave myself lots of opportunities for birdies and the putter was a lot better." Oosthuizen is one shot ahead of Englishman Marcus Armitage, who carded a nine under-par 62 on Saturday to blaze through the leaderboard and enter the final day in second. Armitage, who is looking for his first win on the European Tour, carded six birdies and two eagles. He would have had a share of the lead but for a dropped shot on the 18th hole when he was wayward with his drive. It was a great turnaround for the 32-year-old, who’s score was 10 shots better than his second round 72 on Friday. "That's why we play golf, for days like today," he told reporters. "It was just magic. I haven't been in the lead for a long time so it's good to have a good round and know that you've still got it." South African Jaco Ahlers (68) is alone in third on 13 under-par, while five players, including Brandon Grace (67), are a further shot back but are in contention going into Sunday. The top three players on the leaderboard who have not already qualified will seal entry to The Open at Royal St George's. Oosthuizen has already booked his place after winning The Open in 2010. Oosthuizen will be looking to seal his 10th European Tour title as he celebrates being one of just 10 players to have spent the whole of 2010s in the top 100 on the Official World Golf Ranking.