London - Jenny Gunn held her nerve at the finish as England inflicted reigning champions Australia's first defeat of the Women's World Cup with a dramatic three-run success at Bristol on Sunday.
Victory came down to a tense last over that saw Gunn defend 16, including six off the last ball when Australia's Jess Jonassen failed to clear the rope.
Australia, chasing 260, finished on 256 for eight.
Victory gave England their first World Cup win over arch-rivals Australia in 24 years.
It also saw England replace Australia at the top of the table on net-run rate, both sides now having won four and lost one of their first five group matches.
England and Australia each remain on course for the semi-finals, with all eight sides involved in the tournament playing each other once in the group stage, with the top four qualifying for the knockout phase.
England all-rounder Katherine Brunt starred with both bat and ball, making a rapid 45 not out in a total of 259 for eight before taking two for 42, including the key wicket of Ellyse Perry, who made 70.
A delighted Alex Hartley, who dismissed Australia captain Meg Lanning, the leading batsman in women's cricket today, for 40, said: "What a win, I've not got many words, it's just absolutely fantastic and I just wish it was the final."
Meanwhile Perry was left to rue some unusually slack work in the field by Australia.
"It was a good game of cricket, but in hindsight there were too many extras bowled, 32 is a whole different story at the end of the game and we did well to keep in there at the end," she said.
"We gave ourselves too much to do through the middle of our batting and bowling."
Sunday's other match saw the West Indies beat Sri Lanka by 47 runs.
Both the West Indies and Sri Lanka had only their pride to play for in Derby after they had each lost all four of their previous group games, with the two teams out of semi-final contention.
West Indies, the women's World Twenty20 champions, made 229 for nine, Merissa Aguilleira top-scoring with an unbeaten 46.
They then dismissed Sri Lanka for 182, with Anisa Mohammed taking three for 39.