England must pull off their highest Lord's run chase if they are to record a first victory in 10 Tests and go 1-0 up in the Investec series against India.
Ravindra Jadeja hurt the hosts badly with a counter-attacking, career-best 68 from number eight as India reached 342 all out by mid-afternoon on day four - and therefore set England 319 to win.
The equation appeared sure to be more favourable for Alastair Cook's men when the tourists were 235 for seven, having just lost opener Murali Vijay for an impressive 95, on a cloudy morning.
But Joe Root dropped Bhuvneshwar Kumar (52) on two, and he and Jadeja punished England in a stand of 99 - especially through a 10-over passage of play after lunch which yielded 66 runs.
Jadeja seized the moment either side of the break, unsettling England's bowlers by charging the second new ball and scampering extra runs between the seven boundaries in his 42-ball maiden Test 50.
It was James Anderson who had finally accounted for the admirable Vijay, and before then Liam Plunkett (three for 65), who took England's first wicket of the day when he got one in the right spot to Mahendra Singh Dhoni for Ian Bell to take a neat catch at second slip.
That ended a stand of 79 with opener Vijay, the India captain gone for an uncharacteristically stoic 19 off 86 balls.
Stuart Binny tried a very different approach.
But when Cook took a very good, 'pressure' catch - running back and diving from mid-off with the ball steepling over his head, having slightly surprisingly brought on Moeen Ali - Binny's attempt to dominate came to nought.
Jadeja, demoted a position, immediately attacked Moeen.
He did not always convince, but runs came quickly, and the left-hander soon took on his old adversary Anderson too.
Anderson was wicketless in his first 23 overs.
When he did strike it appeared to be with great significance - Vijay playing perhaps his first false shot, to the 247th ball he faced, and edging behind.
Jadeja, however, began advancing against Anderson - and after Kumar's early escape, Root missing a very sharp chance off Stuart Broad at fourth slip, he played the perfect foil.
He was dropped again, an inside-edge behind off Moeen on 36, but - even after Jadeja fell to a mis-pull at Ben Stokes (three for 51) and another fine catch from Cook running back again, this time from slip - Kumar stayed to complete his third half-century in four innings this summer.
In a series of several notable stumbling blocks already for England, Kumar is pre-eminent - having also taken six wickets in the first innings here - and by the time he was last out, he had ensured a major challenge after all with the bat for Cook and co.
A Dhoni hunch undermined England's prospects when Jadeja had his say with the ball too.
The first delivery from the left-arm spinner, called into the attack for only the seventh over of the hosts' second innings, hit Sam Robson's front pad marginally in line with off-stump.
It was an arm ball, and umpire Kumar Dharmasena decided lbw was in order.
England therefore took tea on 18 for one.