Victory in last month's Seattle Open has strengthened Rachael Grinham's hold on top place in the new October Women's World Squash Rankings, announced today by the Women's International Squash Players' Association (WISPA), as the Australian marches into her 15th successive month in pole position.

The US event's runner-up Vanessa Atkinson, the world champion from the Netherlands, retains her second place in the list, ahead of third-placed Malaysian Nicol David.

Natalie Grainger, of the USA, overtakes Australia's Natalie Grinham to move into fourth place - helped by three WISPA World Tour final appearances by the American this year, including victory in the Vassar College Class of 1932 Open on home soil in February, and the disappointing recent run by the younger Grinham sister who has failed to achieve her seeding in three out of the last four events in which she has competed.

A trio of English players follow the top five - led by Linda Elriani at six; this weekend's Traders United Yokohama Open champion Vicky Botwright at seven; and 22-year-old Jenny Duncalf, who rises to a career-high No8.

Duncalf claimed an unexpected place in the quarter-finals of the Seattle Open after upsetting Egypt's Omneya Abdel Kawy, last month's world No8, in the first round. Kawy slips to nine in the new list.

Another England international is celebrating a best-ever ranking in the October list: Alison Waters, the 21-year-old from London, rises two places to No16 after also making the Seattle Open last eight against expectations. Waters exceeded her seeding position in all but one of the eight WISPA events she has played in this year.

1 [1] Rachael Grinham AUS
2 [2] Vanessa Atkinson NED
3 [3] Nicol David MAS
4 [5] Natalie Grainger USA
5 [4] Natalie Grinham AUS
6 [6] Linda Elriani ENG
7 [7] Vicky Botwright ENG
8 [9] Jenny Duncalf ENG
9 [8] Omneya Abdel Kawy EGY
10 [10] Tania Bailey ENG
11 [11] Jenny Tranfield ENG
12 [12] Madeline Perry IRL
13 [13] Shelley Kitchen NZL
14 [14] Annelize Naude NED
15 [15] Isabelle Stoehr FRA
16 [18] Alison Waters ENG
17 [16] Rebecca Chiu HKG
18 [17] Fiona Geaves ENG
19 [20] Laura-Jane Lengthorn ENG
20 [19] Pamela Nimmo SCO