Kevin Pietersen's 12th Test century helped England recover from a slump to reach 273 for seven on the first day of the third and final Test against New Zealand on Thursday. Pietersen scored 115 for his first Test hundred at Trent Bridge, where he played for four seasons from 2001. He added 161 with wicketkeeper Tim Ambrose, who made 67, for the sixth wicket to revive England after it slumped from 84 for two to 86 for five in the space of 13 balls. England need only to avoid defeat to claim a series victory after drawing at Lord's and winning the second Test at Old Trafford. Pietersen, 27, in his 39th Test, reached his century after tea with a firm drive through cover for four off Chris Martin. England's afternoon slump began when Andrew Strauss fell six balls after lunch when he abandoned the patient approach he had employed in the morning by chasing a wide Kyle Mills ball to give Ross Taylor a head high catch at first slip for 37. Ian Bell played across a straight ball and was lbw for nought to Iain O'Brien after lasting just three balls. His fellow middle-order colleague Paul Collingwood, also under pressure after some mediocre recent form, lasted four balls for no runs, edging Mills to Taylor at slip. Pietersen's confidence grew and his range of stroke-play became more expansive the longer he was in. An off-driven four, a pulled boundary and a flick through mid-on for another boundary, all off paceman Martin, demonstrated this in consecutive overs shortly before tea. He eventually perished when O'Brien rushed him with the third over of the new ball as his half-hearted push gave New Zealand wicketkeeper Gareth Hopkins his first catch on debut. Regular keeper Brendon McCullum is playing solely as a batsman because of a back injury. Ambrose, who scored a century against New Zealand in his second Test in March, ably supported Pieteresen, though the Black Caps may have fed his favored square cut too often with short and wide deliveries. O'Brien returned Test best figures of four for 61 from 20 overs at stumps. Alastair Cook and Michael Vaughan fell before lunch. Stuart Broad was 15 not out with James Anderson on one.