England 215 and 80 for 2 (Cook 37*, Pietersen 35*) lead Australia 280 (Agar 98, Hughes 81*, Anderson 5-85) by 15 runs
Hello, reader. I have no idea what's just happened.

Good luck making sense of this one
We saw three matches in one today.

First, England's ever-reliable portmanteau demon bowler Grammy Anderswann ripped through the Australian lower-middle order, and then at the end Alastair Cook and Kevin Pietersen steadied the ship after Mitchell Starc (in combination, allegedly, with Marais Erasmus) took two in two for the second time in about 24 hours on the stroke of tea.

Cook and Pietersen were both described as becalmed, but in truth Pietersen simply looked too bored to bother playing an attacking shot. Other than an outside edge off Ashton Agar (of whom a lot more later) that would have broken Brad Haddin's leg had he not been wearing pads, and the contemptuous cover drive for four he played next ball as though he were an old-school headmaster caning a pupil for 'answering back', there were few signs that Pietersen had any intention of leaving his bubble. The evening session was little more than a two-hour outdoor net against some disciplined but unthreatening bowling.

In between...

Phil Hughes and Ashton Agar came together at 117/9 after Australia had lost 5 wickets for 9 runs in 5.1 overs to Anderson, who produced a superb spell of controlled reverse swing that was wasted on this batting line-up, and Swann, who made a mockery of his previous struggles at Trent Bridge, turning one square to bowl Haddin and then trapping Swann with one that had just as much work on it (as Sky's rev-counter revealed) but went straight on. Agar changed everything.

While Hughes looked like he had learned nothing from his torrid winter against India, his partner's uncluttered approach took all the pressure off him. Steve Smith had had a similar effect before his needless dismissal, hitting Swann for 16 off 19, but it was Agar's sustained aggression that meant Hughes didn't have to worry about scoring runs and could just concentrate on trying to get down the other end to face the quicks, against whom he looked infinitely more comfortable.

Just as well, really: before the carnage began in the 29th over, Smith had contrived to face 11 of the 16 balls sent down by Swann and had scored at a good rate (16 runs including 2 fours and a big six in Swann's first over), but with his partners giving the impression that Trent Bridge had fitted a revolving door to their pavilion during the ground's remodelling, Hughes was stuck groping around against Swann for 9 of the 11 balls he faced in this period of play, which garnered the grand total of 1 leg bye, and that ball drew a close but unsuccessful lbw appeal.

Then came the new boy. The bare facts are remarkable enough: 98 off  101 balls (the spirit of Virender Sehwag is alive and well), highest score by a number 11 (just), highest ever 10th wicket partnership, the statistical avalanche kept coming (so much so that Cricinfo's stats search engine, friend of scorers everywhere, crashed midway through the afternoon session).

Not only did Agar take the pressure off Hughes by stroking the spinner around at a run a ball (yes, I know he was probably out stumped on 6 but the third umpire would have been better off flipping a coin) but he joined in his newly liberated senior partner's the attack on the suddenly loose England pace attack. Broad and Finn were far too short throughout and were rightly punished, but even the hitherto metronomic Anderson did not come out unscathed. The contrast between his pre- and post-Agar bowling figures tell the story: 16-2-41-5 as against 8-0-44-0 is as much a 'spell of two halves' as you could wish to see. Cook's bizarre field placings and insistence on providing Agar with easy singles like he was his wingman in a provincial nightclub on a Saturday night did not help.

When Agar looped another Broad long-hop down Graeme Swann's throat the crowd barely knew how to react. Swann tried to encourage them with a double-fist pump and roar of encouragement, but the groan was un-ignorable. The standing ovation as he walked off the field, a sheepish grin on his face, will join Clarke b Anderson 0 in the pantheon of great Ashes moments produced this extraordinary Test series. And we've only had two days of the first match. Phew.

What's that? Oh yes, England batted, Starc got Root and Trott in successive balls, Jonathan Agnew moaned about the technology on Twitter, and then Cook and Pietersen had a practice session until close of play. It felt like the cricket universe needed a breather, and it wasn't alone.

Good ball, bad shot
Here we go again! First up, Australia.

Steve Smith, c Haddin b Anderson 53, 108-5: Bad shot. Not just on its own merits, but for the timing. As we discussed earlier he was looking comfortable, particularly against Swann, and until Agar's explosive entry onto the world stage the Smith-Hughes partnership was the only time Australia seemed to have anything approaching a plan. The ball did reverse away, but it wasn't there to hit.

Brad Haddin, b Swann 1, 113-6: Good ball, but a loose shot. It turned square and caught Haddin by surprise, but the bat came down at an angle that was asking for trouble.

Peter Siddle, c Prior b Anderson 1, 114-7: Bad, bad shot. A good diving catch from Prior but this was not a shot you'd readily associate with a man of Siddle's proven fighting qualities.

Mitchell Starc, c Prior b Anderson 0, 114-8: Good ball, indifferent shot from someone with a Test high score of 99. Anderson showed his skill with the old ball, reversing it away from the left-hander, but Starc allowed himself to be suckered into this one.

James Pattinson, lbw Swann 2, 117-9: Good ball, bad review. Pattinson didn't even fool himself when he reviewed this, it was absolutely stone dead. Great areas from Swann though, if it had spun it would have troubled the outside edge but as it was it thudded into the pad.

Ashton Agar, c Swann b Broad, 98: I'm not going to criticise a 'tailender' (he's clearly a hell of a lot better than that) for trying to go to his hundred in a blaze of glory, particularly bearing in mind the earlier Sehwag comparison (Sehwag is the only man ever to go to 300 with a six). It was definitely a bad ball, another half-tracker from Broad, and deserved to end up about 30 rows back. Instead, Swann pouched it at midwicket (and was subsequently inundated with sarcastic suggestions that he should have dropped it in sympathy with his fellow spinner, much to his chagrin).

In mitigation, Anderson and Swann bowled beautifully in the early part of the morning, and what bad shots there were were induced by their precision and sheer skill.

So let's wrap this up with a look at the two English wickets to fall today.

Joe Root, c Haddin b Starc 5, 11-1: The leg-side strangle is pretty much of a giveaway that this wasn't a great ball. It did swing but from far too straight, and Root will be annoyed that he didn't clip this away for four. It's possible he didn't hit it at all, but Cook seemed to decide it wasn't worth the review, so we'll never really know.

Jonathan Trott, lbw Starc 0, 11-2: A fantastic delivery to a set batsman let alone one facing his first ball. This too swung in late but this time the line was perfect and it would have knocked middle out of the ground. The lack of side-on Hawkeye due to badly designed hardware drew complaints, but there was no clear evidence that he hit this.

That's all from me for today, it's been an enthralling and at times exhausting day of Test cricket and leaves the game on a knife-edge going into the third day. See you tomorrow, and may Hashim Amla guide your steps.