Alastair Cook continued to plunder the Australian bowling on Wednesday, becoming the most prolific English run scorer in an Ashes series in eight decades and guiding the visitors into a series-winning position in the fifth Test.Alastair Cook after his century in Sydney. AP PhotoThe 26-year-old opener scored 189 and shared a 154-run sixth-wicket partnership with Ian Bell, who survived a dropped catch and a controversial umpire overrule before notching his first Test century against Australia and helping England reach 488-7 at stumps on the third day, a first-innings lead of 288.England have an unbeatable 2-1 lead and needs only a draw at the Sydney Cricket Ground to claim its first Test series victory in Australia since 1987.Cook had some contentious moments on 46 and 99, both against left-arm spinner Michael Beer, but passed 5,000 career runs and lifted his series tally to 776 runs at an average of 127 with another commanding innings.The 26-year-old Cook scored an unbeaten 235 in the first Test and has only been out five times in the series. He surpassed Herbert Sutcliffe – who scored 734 in the 1924-25 series in Australia – as England’s second-highest scorer in an Ashes series. Only the great Wally Hammond has scored more for England in a series, accumulating 905 in 1928-29 at average of 113.Australia’s Sir Donald Bradman holds the record with his 974 runs in 1930 series in England.Cook was out soon after the tea interval, caught by Mike Hussey off Shane Watson’s bowling to make the England total 380-6.Bell continued to score his maiden century in Australia, but it will remain contentious. He challenged umpire Aleem Dar’s decision when he was caught behind on 67 off Watson’s bowling. The TV umpire Tony Hill ruled that there wasn’t enough evidence that Bell got an edge on a Shane Watson ball that went between bat and bad. But later television technology indicated Bell did snick the ball and Dar’s decision should have stood.advertisementThe English No. 6 was also dropped on 84 when legspinner Steven Smith put down a regulation return catch.Still, after 11 half centuries against Australia, he finally reached three figures. He was caught by Michael Clarke at second slip to give Mitchell Johnson a third wicket six minutes before stumps was called due to bad light.Bell shared century stands with Cook and wicketkeeper Matt Prior, who hit a classic straight six and five boundaries as he raised 50 from 54 balls. He was not out on 54 when play was stopped six overs before the scheduled close.Cook’s innings wasn’t without its anxious moments.He was four runs short of a half century when he appeared to be caught out off Beer’s bowling late on the second day, only for umpire Billy Bowden to refer the decision to the TV umpire, suspecting a no-ball. The third umpire confirmed Beer had overstepped the crease.On 99, Cook clipped a Beer delivery to bat-pad, where Phil Hughes claimed a catch at ground level. But Cook stood his ground despite loud and sustained appeals from the Australians, and got the benefit of the doubt when video replays seemed to show the ball touching the grass millimeters before Hughes got his fingers under it.But otherwise, his eight-hour, 342-ball innings was full of confident, well executed strokes and contained 16 boundaries.England resumed on Wednesday at 167 for three in reply to Australia’s 280 and only lost four wickets in three sessions, including night watchman Jimmy Anderson – bowled by Peter Siddle for seven – and Paul Collingwood – caught for 13 stepping down the wicket to Beer in the morning.