It was a depressing end to a superb innings. As Alastair Cook trudged despairingly from the crease after recording his maiden Ashes century, he was so crestfallen he could barely raise his bat to acknowledge a deserved standing ovation. He was seen in the dressing-room being consoled and congratulated in equal measure by his team-mates, and afterwards he admitted to mixed feelings about what he proclaimed to be the finest innings of his fledgling Test career.

"I wouldn't be human if I didn't get that nagging feeling I could be walking out to get a bigger one and get us closer to the target," said Cook at the close. His departure, caught behind off Glenn McGrath with just 16 balls of the day's play remaining, turned a day of genuine hope for England into another one of grim resignation. With just five wickets remaining and an entire day to survive, Australia seem certain to regain the Ashes by the close of play tomorrow.

Even so, Cook can and should be immensely proud of yet another performance that belied his tender years. This was his fourth Test century in 12 matches, an achievement that brackets him alongside Sunil Gavaskar, Graeme Pollock and Vinod Kambli - all of whom made that many hundreds before their 22nd birthday. "I think it helps being 21," he said of the way he survived yet another intensely humid day, batting for six-and-a-half hours and 290 balls for a nuggety 116.

"I've felt in quite good nick throughout the series but I haven't got a score," said Cook, whose highest to date had been 43 in the second innings at the Gabba. "It's been frustrating to keep making starts but if someone had offered me a hundred, I'd have taken it, especially against Australia in Australia on a turning wicket. But it would be nice if I was not out this evening, and could come back tomorrow and get an even bigger one."

Quite apart from the effort that he showed, his composure at the crease was the most striking feature of his innings. "Lessons had been learnt from Adelaide," he admitted, as he and Ian Bell - who greeted Shane Warne with two sweetly struck sixes - made a concerted effort to stay positive in the face of huge Australian pressure. "We had a change of mentality," Cook said. "The balls come on a bit better here and it's easier to score runs, which was hard at Adelaide.

"We stuck to our gameplans and tried not to get overawed by the situation," he continued, after the pair had added 170 for the second wicket in a partnership that lasted for 56 overs. "Playing Australia in Australia is quite tough. You've got guys with 700 and 500 Test wickets coming at you at two ends, so you are made to work for every run."

That hard work was exacerbated by another typically theatrical performance from Warne, whose appealing was insistent and at times excessive, as he toiled through 31 overs for figures of 1 for 100. "He's always a bit unlucky isn't he?" joked Cook. "There was a bit of banter, but that's just the way the Aussies play their cricket. They play it tough but if someone does well they congratulate them. They've been very good like that." Sure enough, Cook was shaken by the hand by Warne when he notched up his hundred.

Though he was still disappointed by his late dismissal, Cook still held out hopes of the draw, an achievement that South Africa managed in similar circumstances last year at the WACA. "It would be nice if we were still three-down, but we're still in there fighting hard," he said. "I think the pitch will hold up, because there's only a couple of balls that did anything all day. One to KP didn't bounce and a couple have gone through the top, so we hope it'll stay together.

"Unfortunately those last two wickets set us back a bit, but there's a lot of fight in here. KP and Freddie don't hang around, so who knows what can happen if we get through the first hour, first session, like we did this morning. Some people are due some runs, and hopefully they can perform tomorrow."