Alastair Cook scored his second successive century as England finished on 317 for two to give themselves a great chance of taking a 1-0 lead in the Ashes series after the second day of the second Test against Australia.

Cook finished the day on 136 not out with Kevin Pietersen looking ominous on 85 as the pair shared an unbeaten stand of 141 to leave England with a 72-run lead at the Adelaide Oval.

Cook scored 17 boundaries in his 246-ball stay at the crease while Pietersen cracked 13 fours as he moved within sight of his first century for 21 months. Jonathan Trott was also in the runs again with a fine 78.

Pietersen has not scored a ton since his effort in Trinidad against West Indies in March 2009 but he is on the brink here with England dominant despite the near instant loss of captain Andrew Strauss (one) in the first over for a single as they replied to Australia's under-par 245. Pietersen joined Cook at the crease after the Essex opener had shared a second-wicket stand of 173 with Trott, the Warwickshire batsman going just before tea.

England had not made the best of starts, Strauss choosing to leave the third delivery of the day, a length ball from left-armer Doug Bollinger, only to see it clip the top of his off bail.

Trading especially heavily on the cut shot whenever Australia give him the necessary width, Cook reached his hundred with another example of the shot off Xavier Doherty for his 15th four from 171 balls.

The England opener and number three Trott famously piled up a record 329 last week in Brisbane - and when Trott was finally out, they had put on 502 together in almost 10 previously undefeated hours.

With Strauss gone, Trott might have been run out for six as he scampered back from an aborted single. But Doherty missed the stumps from square-leg - unlike Trott himself, who had seen off Simon Katich in similar circumstances on Friday. Michael Hussey then dropped a regulation catch low down in the gully when Trott, on 10 this time, failed to keep an attempted drive at Bollinger on the ground.

Australia fleetingly thought they had the breakthrough when Cook aimed a hook at a good bouncer from Peter Siddle and was given out caught-behind on 64 by Marais Erasmus. An immediate decision to review was vindicated, however, replays showing the ball hitting only Cook's shoulder.

Trott had his third 'life' when Brad Haddin dropped a tough caught-behind chance from a mis-hook off the glove at Ryan Harris. But he was gone two runs later anyway, his favourite back-foot punch to midwicket kept aerial and well-caught by Michael Clarke off the same bowler. But Cook and Pietersen then eased England into the lead and with huge power to add and time on their side, despite an uncertain forecast, to try to force a precious victory.