Prince was the glue to hold the South African innings together after an early burst from Zaheer and Sreesanth had cut the top order to ribbons. He continued from where he left off in the first Test, where he made a battling 97 as South Africa went down. In the absence of Jacques Kallis, who missed this Test with a sore back, there was extra pressure on Prince and he delivered. From the time he came to the crease he occupied it with an unhurried approach, not allowing the pressure of the scoreboard to get to him - at no point did he try to accelerate the scoring, at no point did he play outside his own strengths.
He was no slouch, however, when offered width, and on a wicket that eased out considerably as the day wore on, he drove pleasingly through cover and point. At the end of the day he was unbeaten on 98, on the cusp of his fifth century.
Gibbs's half-century was a timely one for him. The debate over his place in the team was gaining momentum after a run of indifferent scores and he was sent down the order, allowing AB de Villiers to open with Graeme Smith. Gibbs put away his vast array of exciting strokes and toughed it out. He accelerated as he approached and then, in an error of judgment, changed gears. He began to look more like the Gibbs of old, reaching out for deliveries outside the off stump, going forcefully at the ball with hard hands, and just taking the odd chance. On 63 his luck ran out as a wild pull went off the toe of the bat in front of first slip where Mahendra Dhoni snapped up a good catch. Gibbs had added 94 for the third wicket with Prince, pushing the score on to 122, but the manner and timing of his dismissal gave India just a glimmer of hope that they could still end the South African counter-attack in time to keep them down to a low score.
Boucher then set about erasing these Indian hopes. Although he survived a couple of close chances, including lbw shouts that impressed everyone other than the umpire, Boucher looked comfortable and at ease at the crease. He did not look to score at a fast clip, yet his approach and outlook were consistently positive. If anything, it was Boucher's resistance more than that of Gibbs or Prince that really troubled India. The fielding suddenly wasn't as sharp as before, the excitable Sreesanth briefly lost the plot, charging in and trying too hard without much result. Then completely against the run of play, Sreesanth got one ball to shape in nicely and bowl Boucher through the gate for 53.
Prince moved along, collecting runs wherever they were available, safeguarding his wicket at all times, and even severe cramping - the heat and humidity were taking their toll - did not stop his determined march. In an era of dashers, in a team of top-order batsmen playing too many shots too early, Prince the grafter had served his team's cause superbly well.
However, they had, through a late collapse, got themselves back in trouble after a determined middle-order performance had saved them from yet another collpase. The day began badly for South Africa with Smith, ever finding new ways of getting out, pulling one from Zaheer straight up in the air over the slips cordon, where Sachin Tendulkar took a well-judged catch. Hashim Amla was then trapped in front by a Zaheer delivery that pitched in line and swung back enough to win the lbw verdict. 13 for 2 looked bad, but de Villiers made it worse at 28 for 3 when he planted his foot well withing the stumps and drove away from the body. The ball went off the outside edge straight to Tendulkar at slip. Zaheer had put in a sterling first spell of 6-3-5-2.
But Zaheer would not pick up another wicket on the day and only the late-in-the day breakthrough for the largely luckless VRV Singh, got India back in control. VRV had Shaun Pollock well caught at point by Virender Sehwag, and soon after Kumble completely foxed Andrew Hall, trapping him right in front with a googly that the batsman did not pick. Andre Nel fared no better three balls later, and was bowled neck and crop by a similar wrong 'un. That would prove to be the last over of the day as the batsmen accepted the offer for light. India were keen to wrap up the innings, but nevertheless will be well pleased with how events panned out.
Dileep Premachandran in Durban
Highlight of the day: When Herschelle Gibbs is good, he can be very very good. Some of the drives he played after lunch were simply majestic, and there was one carve over point that brought back memories of that rollicking 175 at the Wanderers in the 438 game.
Lowlight of the day: Step forward Gibbs. Having cruised to 63 from 88 balls, he played a truly appalling shot to a Sreesanth delivery that climbed a little. It allowed India a way back when it appeared that they might have lost their way.
Shot of the day: The Gibbs tale continues. Sreesanth pitched one up, trying to entice the drive early in his innings, and Gibbs responded with an absolutely glorious drive that rocketed into the boundary boards before the man at cover could barely stir.
Ball of the day: The 140.2 km/h special from Sreesanth that made a hideous mess of Mark Boucher's stumps. Again, the seam position was sensational, and it came in enough with the angle to sneak through Boucher's prod.
Catch of the day: Gibbs may have played a terrible shot, but it still needed a magnificent full-length dive to the right from Mahendra Singh Dhoni to send him on his way.
Message of the day: And just when Graeme Smith thought it couldn't get any worse. Two South African fans, shirtless and no doubt fuelled with lager, took out a banner soon after lunch. "Smith: Hope you'd scored more with Minki [van der Westhuizen]," it said, a reference to his former girlfriend. So much for not kicking a man when he's down, and out [for 5].
Off the park: Sachin Tendulkar made a quick trip to the hospital after dropping Ashwell Prince off the bowing of VRV Singh before tea. X-rays revealed no fracture, and the bruising on the right thumb shouldn't hamper him unduly when it's India's turn to bat.
Anand Vasu is assistant editor of Cricinfo