Sexton, playing only his second Test, kicked five penalties in another composed display that fully justified his selection ahead of veteran Ronan O’Gara.

O’Gara, dropped for the first time against meaningful opposition since 2003, watched from the bench as his grip on the number 10 jersey loosened further.

The afternoon’s only try was supplied by South Africa flanker Schalk Burger in the 16th minute and Ireland, in control throughout, will have been disappointed by their failure to breach the visitors’ defence.

Burger celebrated by hoofing the ball into the stands, provoking a chorus of jeers from angry home fans who had not forgotten his gouging of Luke Fitzgerald during the Lions’ tour of South Africa earlier this year.

Tempers flared with just two minutes on the clock with only a warning from referee Nigel Owens interrupting play.

Throughout the first quarter the Springboks’ line-out was being heavily disrupted by Ireland, who attacked the breakdown with gusto.

Quick thinking from Stephen Ferris forced one turnover that allowed Jamie Heaslip and Tommy Bowe to break free and the Springboks, in disarray, infringed.

Sexton stepped up to land a monster penalty but the tourists' response was emphatic with Burger galloping over.

Back-pedalling furiously at a scrum, they conceded a penalty that the Springboks used to build pressure before Morne Steyn sent Burger over and then added the conversion.

The frantic pace continued as Brian O’Driscoll somehow burrowed through a mass of South African jerseys and Ireland poured forward with Heaslip and Ferris making wrecking-ball runs.

Crucially, however, a three-minute stint spent pounding away at the Springbok line went unrewarded when the Irish were penalised for holding on beneath the posts.

Steyn booted a drop goal to rub their noses in it and despite controlling territory and possession, Ireland found themselves trailing 10-3.

Showing superb composure, Sexton slotted a tricky penalty to reduce the deficit and then watched as Steyn squandered six points by missing two long-rage kicks.

Another penalty was conceded at the scrum and once again Steyn missed the kick, though it was a third penalty that tested his range to the limit.

Ireland's scrum suffered its biggest implosion yet, but they restored morale with two Sexton penalties that nudged them 12-10 ahead.

Winger Keith Earls was bundled into touch in the left corner by Steyn and JP Pietersen as the Irish onslaught continued.

South Africa, wilting beneath the relentless pressure, conceded another penalty but this time Sexton missed.

Substitute Ruan Pienaar struck the uprights with a penalty and then Sexton missed for a second time.

South Africa managed to launch one final assault that saw Tendai Mtawarira rampage down the right wing, but Ireland held firm to clinch their third successive home victory against the Springboks.