By Matthew Sherry
With England stumbling to nought for two in the first over as they pursued 190 versus Sri Lanka, the game appeared to be heading only one way.
But Hales put on 152 with Eoin Morgan, who struck a crucial and restorative 57.
However, even that paled in comparison to his partner’s heroics, the opener becoming England’s first format centurion with a 64-ball 116 not out that featured six sixes.
“That's a very special knock, one of the best I've seen in an England shirt,” enthused Broad.
“To take the responsibility and have the run-rate that we had, to keep up with that all the way through, and then to win it with a few balls to spare is very special.
“It's the best we've seen this winter in an England shirt because it was match-winning. The calmness he showed to keep us up with the rate all the way through and the skill he showed to clear the ropes at the end.
“There's been some very special knocks in the Test match stuff that I've been very lucky to witness but on the biggest stage in a World Cup, in conditions that are a little bit foreign for us, it’s one of the best knocks I’ve ever seen.”
For his part, Hales admitted he had not yet come to terms with the scale of such a Herculean effort.
"It’s definitely my best day for England, without a shadow of a doubt," said the 25-year-old. “It's an amazing feeling and it hasn't sunk in yet.
“Centuries in this format don't come along very often and I've got out a couple of times in the 90s, so I was pleased to get over the line.
“I always had the confidence I would get the chance again and I'm buzzing it came in a winning side and in a huge fixture for our country.”
Hales hit the winning six off Angelo Mathews, an almighty strike that almost cleared the stands on the leg side.
He celebrated by striking a pose out of the Andrew Flintoff playbook, arms raised aloft as he surveyed his achievement.
“It was a great feeling, especially in a game like that," he said. “He bowled the ball exactly where I wanted him to and I managed to get it over the ropes.”
Hales, too, was quick to pay tribute to Morgan, his partner in crime for much of the remarkable riposte.
"I started to believe we could do it with probably six or seven overs left," he explained.
"We needed about 12 an over so we always knew it would be a tough ask, but Morgy played brilliantly. We knew if we stayed in the game, we had a chance. Morgan made my job a lot easier.
“And then Ravi (Bopara) came in against the dangerman (Lasith Malinga) and hit his first two balls for four. It was brilliant to see."
Such was the quality of Hales’ knock, even the opposition were quick to offer praise.
“Alex played really well, exceptionally well,” said Sri Lanka skipper Dinesh Chandimal. “Credit goes to him and Morgan. They batted exceptionally well."
Chandimal confirmed that Mahela Jayawardene, who top-scored for Sri Lanka with 89, dislocated a finger while attempting to catch Hales.
With Sri Lanka not playing again until Monday's meeting with New Zealand, Jayawardene, who will retire from the Twenty20 internationals after this tournament, has a chance of featuring then.
Chandimal said: "Mahela's finger is dislocated and I think he will be going in for X-ray. Hopefully, he will be fit for the next game."
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