Siddle lost his position when Clark recovered, but he got back into the side for the first Test against South Africa at the WACA due to Clark's elbow injury recurring, and during Australia's back-to-back series against South Africa he solidified his place in the team. He broke through with three wickets in front of his home crowd at the Melbourne Cricket Ground during the Boxing Day Test Match against the Proteas on his way to figures of four for 81 in the first innings. Siddle backed this performance up in the next Test at the Sydney Cricket Ground, taking five for 59 in South Africa's first innings. His efforts were not enough, however, to prevent Australia from succumbing to a historic home series defeat.