England finished the first day of the final Test on 199 for five after losing Alastair Cook and Nick Compton in quick succession.
Pietersen holds fast for England after sticky start against India
Alastair Cook's tourists, needing a draw in Nagpur to close out an historic series victory, lost both openers - their captain and Nick Compton - to India's lone pace bowler Ishant Sharma inside the first hour.
But Pietersen (73) and Jonathan Trott then shared a hard-working stand of 86 in 39 overs after England had chosen to bat first.
Pietersen had to play a very different game in his 108-ball 50 today to the century with which he transformed proceedings in England's famous second-Test victory in Mumbai last month.
Extreme conditions here at the VCA Stadium dictated that patience and watchfulness were a necessity, even for a batsman of his world-class talent.
The same will surely pertain all match, and may well mean England have fared acceptably at least - especially after a second 50 partnership, unbroken between Matt Prior and debutant Joe Root - on a surface precluding fluent strokeplay.
Compton was the first to be undone in slow-motion when a short delivery produced only looping, disorientating bounce.
He set himself with reflexes trained for a pitch somewhere within the usual pace parameters.
As the ball died off the surface, Compton's bat was therefore thrown into position too quickly and resulted in a thin edge which barely carried to the wicketkeeper.
Cook needed 15 balls to get off the mark, as Pragyan Ojha took the new ball in the absence of a second seamer and tried to out-bore the England captain with a seven-two leg-side field and consequent negative line.
Trott contributed England's first boundary, a straight-driven four when Sharma helpfully took the pitch out of the equation with a half-volley.
But the number three was fortunate to survive on seven when he played too soon at a length ball and was hit on the pad.
Sharma was convinced the lbw was stone-dead, but umpire Kumar Dharmasena made the marginal call that ball had hit pad just outside the line of off-stump.
Cook found himself on the other side of a similar ruling soon afterwards from Dharmasena - and although it looked as if he was hit outside the line, this time he had to go lbw.
England were in danger of fluffing their lines just when they need one more confident performance to complete their mission improbable on this tour.
But Trott and Pietersen provided some much-needed stability as they gradually attuned themselves to an unfamiliar experience, even by sub-continental standards.
Pietersen became sufficiently in sync to loft leg-spinner Piyush Chawla over mid-on for two boundaries in one over.
By early afternoon, he was also leg-glancing Ravichandran Ashwin for his seventh four to reach his half-century.
Trott dug in too for 133 balls until a misjudgment against slow left-armer Ravindra Jadeja saw him wave through an arm ball which bowled him off-stump.
Ian Bell disappointed, making only a single in 28 balls before poking a straightforward catch to cover off Chawla.
Pietersen had escaped a half-chance on 61, when Cheteshwar Pujara could not quite gather a tough low catch at midwicket off Sharma. He shepherded Root through to tea.
But there was to be no record-equalling 23rd Test century, Pietersen neatly caught low down by Ojha when he again chipped to midwicket - this time advancing to Jadeja.
It was the latest in a series of apparently unforced errors which had led to England wickets. But it would be missing the point to view them in isolation, without reference to the arduous process of trying to make runs in between with so little pace and bounce on the batsman's side.
Prior joined Root, and the struggle continued - favourably for England, though - for the remainder of the evening session.
Prior, like Pietersen, was forced to bat against type - while Root impressed with his defensive technique and willingness to meet spin with bat rather than pad even in the absence of DRS.
By the close, the jury had to stay out on which team was ahead of the game.
For England, after their decidedly sticky start, deferred judgment was a tolerable outcome.
Meanwhile Stuart Broad and Steven Finn are both to return home early from the tour through injury.
Both had scans two days ago, Broad on his left heel and Finn his lower back, and the results ruled them out of the final Test which began in Nagpur today.
Twenty20 captain Broad will also miss two matches against India in the shortest international format next week, when Eoin Morgan will instead lead the team.
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