Shortly after tea, England were 247 for four with Pietersen completing his fifth Test hundred with a single. Ian Bell, going for his third hundred in as many Tests, was unbeaten on 13.

At tea, England were 224 for four after Pietersen, given not out on two when caught behind and caught off a no-ball on 29, had found his form.

Together with Paul Collingwood (31), Pietersen had put on 82 in 23 overs as England recovered after lunch.

Pakistan, beaten inside three days during England's innings and 120-run victory in the second Test at Old Trafford, which put the hosts 1-0 up in the four-match series, had fought back well to reduce their opponents to 110 for three at the interval.

Pietersen resumed on 17 not out after Alastair Cook (23), off the last ball before the break, was caught and bowled low down by pace bowler Umar Gul after the left-hander - who'd scored centuries in the first two Tests - got a leading edge.

Collingwood got off the mark in style by pulling Gul for six. Pace bowler Shahid Nazir, playing his first Test in seven years, thought he'd had Pietersen caught behind off the inside edge but Australian umpire Darrell Hair signalled a no-ball.

To make matters worse for Nazir, who'd earlier marked his return by taking one for 19 off eight overs, the batsmen ran after wicket-keeper Kamran Akmal threw the ball up in celebration.

Pietersen then lofted leg-spinner Danish Kaneria, who'd taken just seven wickets for 302 runs in the previous two Tests, over long-off for six before driving Nazir for two straight fours.

And a pulled four off Nazir took South Africa-born Pietersen to a 79-ball fifty with one six and eight fours.

Collingwood had looked untroubled until he miscued a pull off Gul and holed out to Taufeeq Umar at mid-wicket, leaving England at 192 for four in the 50th over.

Bell, who scored 100 not out in the drawn series opener at Lord's and an unbeaten 106 at Old Trafford, got off the mark with an off-driven four off Gul.

Pietersen then damaged the bowler's figures further by pulling a good length delivery for four before going down on one to cover-drive him for four.

Umpire Billy Doctrove was then forced to duck as Pietersen drove a low straight six off Kaneria.

England started briskly but lost both their openers, Marcus Trescothick (28) and captain Andrew Strauss (36), who'd won the toss, with the score on 67 after they'd dominated the first hour.

But previously wayward paceman Mohammad Sami, struck in the first over after the drinks break when, having switched ends, he took a juggling caught and bowled chance to get rid of Trescothick, early on a drive.

And four balls later fellow left-hander Strauss exited when he edged Nazir to Younis Khan at second slip.

Nazir was unlucky not to have Pietersen, on two, caught behind with England 77 for two. Hair rejected the appeal but replays indicated Pietersen had inside-edged the ball on to leg.

Strauss had earlier decided to bat despite the overcast conditions which usually assist swing bowling at Headingley.

None of Pakistan's bowlers had the pace to escape with bowling short and a boundary was often the result when they did.

In the ninth over Nazir, in for the dropped Abdul Razzaq, came on for his first bowl in Test cricket since appearing against Sri Lanka at Lahore in 1999.

England made one change with Chris Read replacing wicket-keeper Geraint Jones, dropped because of a lack of runs.

Pakistan made three changes with Salman Butt, omitted at Old Trafford, restored as an opener in place of the injured Imran Farhat while all-rounders Razzaq and Shahid Afridi were dropped.

Specialist opener Umar came in for his first game of the series.