World number 40 Rooney defeated Willstrop 11-4, 11-5, 11-8 at the National Squash Centre in Manchester, England.

The pair have a close relationship and were both coached by Malcolm Willstrop, father of James, who died in May from cancer.

Fellow Englishman George Parker, a wildcard entry ranked number 39 in the world, also sprung a surprise by defeating Scotland’s Greg Lobban, the world number 28, 11-5, 11-6, 11-3.

Elsewhere in the men’s draw, world number 21 Adrian Waller of England won the only contest to go the distance today, with the world number 21 coming from behind to defeat Youssef Soliman of Egypt 7-11, 11-6, 11-6, 7-11, 11-9 in 85 minutes.

The top eight men’s seeds will enter at tomorrow’s second round stage, with top seed Marwan ElShorbagy of Egypt taking on wildcard Parker.

In the women’s draw, world number 44 Jasmine Hutton beat higher-ranked opponent Lucy Turmel, the world number 30, in an all English meeting 11-7, 11-5, 11-7.

Lisa Aitken also caused an upset by beating world number 24 Donna Lobban of Australia, with the Scottish player victorious in the only women’s contest of the day to go the distance, by a scoreline of 8-11, 4-11, 11-6, 11-8, 11-4.

The top eight women’s seeds also enter tomorrow in round two, with top seed Hania El Hammamy of Egypt facing Rachel Arnold of Malaysia, after Arnold today beat Alexandra Fuller of South Africa 11-9, 11-6, 11-3.

There will be new names on the men’s and women’s trophies with both Egyptian defending champions Mohamed ElShorbagy and Nour El Tayeb absent from the field this year.

The PSA World Tour silver event has twice been postponed this year, firstly in April and secondly in June.

The postponements came about because of concerns surrounding international travel into the country and contract tracing regulations imposed by the British Government.