Praveen Kumar will tell you that aggression isn't only about pace. He is generally a fiery man on the field, finishing every ball with a scowl, but it isn't about the body language either. It's the nature of his craft. You can't be a swing bowler without being aggressive. There is no other way to swing the ball than to pitch it up, and pitching the ball up is as aggressive as banging it short. If anything, it takes more courage - much more so at Praveen's pace.

Kevin Pietersen, his former captain at Royal Challengers Bangalore, once suggested to him that he could become unplayable if he managed to crank up his pace by five to 10 kph. It's not known how much of Pietersen's language Praveen understands but the tale goes that he gave his captain a smile and carried on with his business. He is a man with a keen understanding of his strength, and perhaps his limitations. He is no Dale Steyn.

From the moment it became clear that Zaheer Khan would watch the rest of the innings, and quite possibly the rest of the match from the players' balcony, India knew they needed nothing short of heroism from a couple of their remaining bowlers. As it turned out, two of their more experienced bowlers simply wilted. It was Praveen, playing only his fourth Test and by no means a certainty to make the cut before the Test, who ensured that India did more than chase the ball all day.

In overcast and swinging conditions on the first day he bowled well enough to have ended up with a couple of wickets. But some balls swung across the breadth of the stumps, making batsmen look helpless yet comfortably eluding the edge. Friday's sun brought blessings for batsmen, who began the day by driving confidently in front of the wicket and, when the first ten overs passed by without a wicket, it seemed the only twist possible in the match would come from the bowling change. The ground had been abuzz in the morning about the possibility of Mahendra Singh Dhoni filling up the bowling vacancy.

But Praveen, having swung most balls away from the right-handers, provided the breakthrough by swinging one back in to Trott and from here he always remained a threat. Four of his wickets came in two overs but he beat the bat in almost each of his overs as the seam stayed straight and the wrist manipulated the swing. Twice he got left-handers by swinging the ball in to them from outside the off stump. It's almost the perfect ball to the left-handers early in swinging conditions, but also the toughest to deliver for a right-hand bowler from over the wicket.

He also needed to be mindful of staying away from the centre of the pitch on his follow-through after being on the verge of a warning yesterday. He did so not by making changes to his bowling action, but by bowling slightly wide and delivering quite a few overs from round the wicket. The lines were straighter, though, the length marginally fuller, and while Praveen mostly delivers outswingers, the perennial threat of the one that bends back makes his stock ball even more effective.

But with his colleagues being lacklustre - Harbhajan Singh, who would have been expected to lead the attack, was disappointing again, offering neither control nor the sniff of a wicket - and the fielding being decidedly plodding, England ran up a score that will allow their bowlers to bowl to aggressive fields. India's batsmen have to rise above their collective record at Lord's to ensure that their thin attack isn't subject to further brutality in this Test, but Praveen has ensured that amid the wreckage today, there was at least one good story. And they will stop making fun of his pace, for a few days at least.

But in a quiet moment, while they lick their wounds, India might rewind to a crucial moment yesterday before it really unravelled for them. Zaheer Khan had produced a wonderful sequence of balls to earn an edge from Jonathan Trott, who has been generally unremovable at Lord's. Dhoni began going to his right as the man with the gloves must, but he stalled midway, allowing the ball to sail past. It was within the reach of Rahul Dravid at first slip, but Dravid was both unsighted and put off by Dhoni's initial movement and ball streaked to the boundary. Midway through his next over Zaheer walked off with a twinge in his right thigh.

Cut to today; midway into the second session Praveen Kumar, the new leader of the Indian attack, curved it away from Ian Bell to induce a meaty edge. Dhoni's dive was fully committed this time and he came up with the ball a few inches from the ground. There was a fundamental difference between the two instances. The cordon behind the wicket was so tight almost all day yesterday that the fielders could have touched each other by merely extending their arms. Today they switched to a more traditional formation with a healthy distance between the wicketkeeper and first slip. It was clear to Dhoni that only he could reach the ball.

The cordon has also been standing deep. The day before the Test Kiran More, who has experience here, was heard advising Dhoni that Lord's is a ground for standing forward to negate the wobble that the ball generates after passing the bat. But Dhoni, and it's the wicketkeeper who sets the distance, has been standing deep despite collecting plenty of balls below his knee, and indeed some at ankle height. Ishant Sharma, who didn't have the best of days, did induce an edge from Pietersen long before he got to his hundred. It was off a drive, and there is never anything coy about a Pietersen drive, and the ball travelled straight to second slip, but fell comfortably short.

Small things like these can sometimes turn a Test.

Sambit Bal is the editor of ESPNcricinfo