1. Bell, Trott Clangers
Is a hint of desperation creeping into the England top order? Kevin Pietersen's belligerence and James Taylor's terrier-like tenacity at the crease have kept the hosts in the match, but the modes of Jonathan Trott and Ian Bell's dismissals earlier in the day suggest a flustered mindset.
Both Trott and Bell have cemented their Test spots with calm, controlled batting performances in the past, but today both were dismissed flashing unnecessarily outside off-stump. Trott was the first to go, flinging his arms out into a cut and edging an outswinger into Graeme Smith's lap at first slip. It was the fifth time he's fallen to Dale Steyn in Tests.
Then, minutes before tea, Bell chased a Jacques Kallis outswinger while rooted to the crease and offered another simple chance to Smith in the slips, exposing the debutant Taylor in trying conditions. Gifting the opposition wickets in this manner is so out of character for both men, and such errors are not the sort you'd expect from the top order of the world's No. 1 Test side.
2. The Long And The Short Of It
Taylor will have been in a cauldron of pressure he won't have experienced anywhere else in his cricketing career when he walked to the crease with an-over-and-a-bit to go before tea. With three slips behind him waiting for the edge Kallis greeted him with a 145kph bouncer that looped over both the batsman and a leaping AB de Villiers, but Taylor displayed a sang froid that belied his inexperience and was off the mark with a crunching off-drive off Imran Tahir.
After the interval, he had the pleasure off facing Dale Steyn and Morne Morkel, who at 6' 8" towers almost a-foot-and-a-half over the 5' 4" Taylor. Both men, and Vernon Philander, occasionally troubled him outside off-stump on a pitch that still had plenty in it for the bowlers but the edge wasn't found. Taylor survived a run-out chance - always a risk when batting with KP - late in the afternoon and had the better of a series of mini-battles with Morkel before his eventual dismissal to the loping South African quick for a gritty 104-ball 34.
He'd helped the marauding Pietersen to put on 147 for the fifth wicket to take the wind out of South Africa's sails after the visitors had made a series of incisions into the top order in the morning. Taylor, who is just 22 and could well have a fruitful career ahead of him, has probably done enough to ensure an extended run in the side this summer.
3. King Kev
And so to Kevin Pietersen. It's not hard to understand why KP has played this way so often against South Africa. The combination of his decision to settle in England, his brash character and his eye-catching batting was always going to be an explosive one, and his innings today brought back memories of his blazing start against the South Africans in one-day cricket eight years ago.
Then, as now, England were on the ropes and it brought out KP's bellicose best. At Bloemfontein, East London and Centurion he blazed his way to three incandescent hundreds. The fire in his belly was back at Headingley today, as he shrugged off a chance given to Hashim Amla at short leg and motored to a 142-ball ton - his 21st in Tests - and in the course of his knock passed 7,000 Test runs, putting him eighth on England's all-time list of Test run-scorers.
His battle with Dale Steyn made for particularly enthralling viewing, as methodically took the world's best fast bowler apart with a series of meaty drives and pulls. The fight seemed well and truly won when Pietersen shellacked a towering straight six straight over Steyn's head, and Graeme Smith promptly pulled him out of the attack.
Pietersen has divided opinion at home as much as he has overseas, if not more so, but it's days like this that continue to endear him to the British public. He got an ovation when he passed the 7,000-run mark, another, louder one when he reached his century and yet another when he walked off with 149 unbeaten runs under his belt.
4. Toothless Tahir
In amongst the action, Imran Tahir bowled 16 largely featureless overs, being milked for more than four-an-over and never really threatening. Tahir has done his bit as South Africa's spinner in his fledgling Test career. A bowling average in the mid-30s is decent, but Tahir was picked because he was the anti-Harris and there's a persistent feeling that South Africa haven't quite worked out how to use him yet.
Tahir hasn't had the chance to lead the attack in Tests yet, but has only played in South Africa, New Zealand and England since his Test debut at Newlands in November last year. Conditions haven't exactly suited him but, as Pietersen showed with his dismissal of Jacques Rudolph, the Headingley pitch has something in it for the spinners. Tahir also has good experience of English conditions, having plied his trade - and prospered - for Hampshire, Middlesex, Warwickshire and Yorkshire, and South Africa need to start asking more of him.
5. Knee Jerk
It was Steven Finn's knee that grabbed the headlines on the first day, but today it was Graeme Smith's turn to get some attention. With the shadows lengthening across the ground and less than 10 overs remaining in the day, Smith chased a Matt Prior cut out to deep point.
As he slid to stop the ball his knee plugged in the turf, twisting under his bulky frame, bringing to mind Simon Jones' career-threatening knee injury in the 2002/03 Ashes. Smith initially tried to walk the pain off, but quickly sank to the ground and gestured to the team's physiotherapist. He was helped, limping, from the ground and it remains to be seen how badly he's been injured.
With the world No. 1 Test ranking at stake, South Africa will be desperate for their captain to remain in the game and his efforts are sure to be needed in the visitors' second innings.