England captain Stuart Broad believes his side can become unlikely challengers at the World Twenty20 after throwing off the shackles in a thrilling win over Sri Lanka.

It may seem premature for Broad to be publicly pondering such things, with England still needing to beat South Africa on Saturday to avoid an early exit, but the brevity of the competition means trophy-winning momentum can be pieced together in a matter of days.

Now, having overturned the world's number one T20 side in some style - Alex Hales playing the innings of the tournament as he clubbed an unbeaten 116 in 64 balls - England are starting to seem like less fanciful contenders.

"T20 is a momentum game and the innings we chased against Sri Lanka was one of the best I've ever witnessed," said Broad.

"The confidence and belief we will get from that going into our final two group games is going to be huge. It's in our hands a little bit now.

"If we had lost against Sri Lanka we were pretty much out of the World Cup. With that sort of pressure, it's exciting to see players come through that.

"We have got two group games left and we're very confident we can do well in those.

"We know what these tournaments are like, if you can get on a run, if you can get a few guys going you can win these tournaments and it's not out of our grasp."

Asked if England were finally ready to turn a corner and put a miserable few months behind them, Broad adopted an uncharacteristically wistful tone.

"Touch wood...we've got to be getting there haven't we?" he said. "We have had a couple of things go against us, Mother Cricket has not looked after us particularly well over this winter."

If they are to complete their unlikely swing in fortunes, England cannot afford to sit back and rely on a Hales storm every time.

Even that may not be enough next time if they do not knuckle down and improve their performance in the field.

A total of four catches went down in Sri Lanka's innings of 189 for four, with a botched run-out by Jos Buttler adding to an unusually ragged showing from the boys in the 'solar red' shirts.

There is also room for improvement in the bowling ranks, where Tim Bresnan and Broad himself have yet to hit top gear.

"Our batting is obviously firing but we need to up the standard of our fielding," the skipper admitted.

"Our fielding has been our strong point in the last three weeks, we have been awesome, so to miss chances against key men hurt us.

"We could have easily restricted Sri Lanka to 150 on that wicket: we could have done, but we didn't.

"If we take our catches we will stand ourselves in a much better chance on Saturday."

Broad chose not to blame the sloppy catching, for which Bresnan, Jade Dernbach and Ravi Bopara were all culpable, on the wet ball.

Evening matches in Chittagong have been badly affected by dew so far, making the ball hard to grip for bowlers and tricky to cling onto in the field.

Even Sri Lankan veteran Mahela Jayawardene shelled Hales on the boundary as the ball slipped through his grasp.

But Broad, searching perhaps for one too many positives, insists England's struggles in those conditions leave them better equipped than the Proteas, who have yet to play a late match.

"We have got the advantage of having played a few games under the lights here," he said.

"Conditions are extremely different from anything we've had before and South Africa haven't played under the lights yet.

"But we've got the experience of that. It can give us a little bit of an edge if we use it wisely."