Images: Ice-cool Cook emerges from dark days to deliver

England opener Alastair Cook's 438 runs in three innings has made him the dominant player of the Ashes series so far, making it hard to believe that 14 weeks ago he was fighting for his place in the team.

Cook, who has scored 67, 235 not out and 136 not out to help rescue a draw in the first Ashes Test and take control of the second, had managed just 106 runs in eight innings going into the third Test against Pakistan in late August.

The 25-year-old left-hander's response was to score an uncharacteristically aggressive century at the Oval and pretty much secure his place in the touring party.

Even still, his paltry average of 26.21 in 10 Ashes Tests had some questioning whether he should be retained as an opener for England's campaign to win a first series for 24 years in Australia.

"It's always disappointing when you get criticised but I deserved it," Cook said on Saturday. "That's part and parcel of professional sport.

"And how I dealt with it at the Oval has given me a lot of confidence when the situation gets tough.

"When I needed it most I could deliver it. And coming here to Australia when the side needed it most, I have delivered so far."

Cook conceded that during the slump he had wondered whether the runs would ever return but having former England captain and opener Graham Gooch as batting coach was a bonus.

"You do have those dark thoughts," he said. "But having Goochy around helps, he knows what it's all about being an opening batter.

"The opening bowler is paid to get you out. Some days he does get you out. When you get the conditions like they were today, it's important to cash in."

Cook has now batted in all but 11.2 overs of the two Ashes Tests so far, a gruelling schedule even if the temperatures at the Adelaide had not hit 37 degrees Celsius as he batted through the day on Saturday.

"At tea, I was really tired," he said. "It was up there with the hottest conditions I've batted in. It was physically quite hard after last week as well.

"I'm quite lucky in that I don't sweat that much, though. I just used one pair of gloves all day while Kevin (Pietersen) was changing his every three overs. I'm built so I don't really get that hot or sweat that much."

Cook has now batted for more than 20 hours over the two Tests but maintaining concentration is all part of the opener's art.

"When you get into this rhythm in batting it's all about not trying to break it. Just focusing on the next ball, and getting through that next 20 minutes," he said.

"If you ever need a reminder of how cricket changes, you only need to look at me last summer. The art of batting is concentrating for long periods of time and not making mistakes."

England have first innings lead of 72 with eight wickets in hand going into the third day at the Adelaide Oval but Cook has not intention of stopping his accumulation of runs yet.

"It's important that we keep batting tomorrow, get through that first half hour and get a really big score," he said.