Sky Sports - England in Australia

Alastair Cook famously put Australia to the sword in the 2010-11 series. This time he goes into an Ashes series as a marked man, the England captain.

Whether Australia can do anything about the 28-year-old Essex run-machine is another matter. With 25 Test centuries to his name and 7,524 runs, he looks likely to shatter all England's batting records before he is done.

It has not always been so of course. His first Ashes series was 2006-7 in Australia, where he scored just 276 runs in 10 innings - 116 of them in one knock - was a rough baptism of fire. His technique came under huge scrutiny. Was it up to scratch at the highest level? A tendency to play around his front pad was causing major problems.

Away he went, ironed out the kinks in his defence, and the runs flowed - but his second series against the Aussies, in England in 2009, was little better than the first - just 222 runs at 24.77.

But third time was indeed lucky. In 2009-10, he scored an incredible 766 at 127.66. Three big centuries, two more 50s - it was 'Cook's Ashes'.

In his first series as captain, against India last year, he averaged over 80, scoring three centuries in England's fine series victory.

The average dropped to 38 in New Zealand, but was back above 50 for the recent home series with the Kiwis.

Cook was second youngest player to reach 5,000 Test runs, behind Sachin Tendulkar. He was the youngest to reach 7,000 runs. No Englishman has scored more than his 25 Test centuries - and don't forget 29 further half-centuries. That conversion rate is impressive - once he's in, Cook is hard to get out

But how will he perform as captain in his first Ashes series? New Zealand captain Brendon McCullum says Cook is a "genius", the best batsman in world cricket since Sir Donald Bradman. He is England's best and most consistent run-scorer. He potentially holds the key to the Ashes. But if he succumbs to the pressure of being captain in an Ashes series, the Aussies have a chance.