Misfortune of the day Morne Morkel should have had a wicket with his fourth ball of the morning when he induced Kumar Sangakkara to drive. A healthy outside edge found its way to Graeme Smith at first slip who waited for Mark Boucher to dive to his right and attempt to grasp it from out of his range. The result was the two senior men looking at each other in horror as the ball went between them. Morkel was distraught and Sangakkara went on to score a fluent 108, which could well take the match out of South Africa's hands.
Shot of the day Sangakkara made the most of his lifeline and played a series of sublime strokes, none more majestic than the upper cut off Marchant de Lange. He tried to butter Sangakkara up with a few short balls but then offered him too much width. Sangakkara accepted by stepping onto his tippy toes, arching his back and slapping the ball over the slip caudon, who could only watch and admire.
Breakthrough of the day Sri Lanka went about their business of building a sizeable lead in fairly quiet fashion. Sangakkara and Thilan Samaraweera had put on 94 runs together and both looked in control when Imran Tahir ended their stand. He slipped in a slider, which deceived Samaraweera - usually a confident and competent player of spin - and snuck off the inside edge onto his stumps. Tahir's manic charge around the field that normally follows a wicket became a more subdued run towards Mark Boucher as short-lived relief passed through the South African camp.
Words of the day When Sri Lanka's lead crossed the 400 mark and South Africa's weary attack looked no closer to taking a wicket, one would have thought they would have had nothing to say. But Dale Steyn had something to get off his chest and he let Dinesh Chandimal know in the same over the young wicketkeeper had taken a boundary off him courtesy of AB de Villiers' overthrows. Steyn bowled a few short balls and gave Chandimal a verbal working over. It turns out it may all have been wasted because Chandimal doesn't speak much English.
Firdose Moonda is ESPNcricinfo's South Africa correspondent