Germany's Simon Rösner defeated world champion Karim Abdel Gawad ©PSA

Both world champions were defeated today as action began at the Professional Squash Association (PSA) World Series Finals in Dubai.

Egyptian pair Karim Abdel Gawad and Nour El Sherbini - the men's and women's world champions respectively - went down to Germany's Simon Rösner and England's Sarah-Jane Perry as group matches started the tournament in the United Arab Emirates.

Rösner claimed a superb 11-9, 8-11, 11-7 win in the best-of-three format to oust the top seed in Group A at the Dubai Opera House.

"We played some incredible squash today, I thought I managed to play aggressively and at the same time I didn’t make too many errors, which really helped," said the German.

The prestigious tournament only features the top eight men's and women's players on the Road to Dubai standings.

England's Perry claimed a huge scalp as she came from behind to defeat world number one El Sherbini 9-11, 11-9, 11-4 in Group B of the women's tournament.

"I'm feeling pretty amazing, I think this is the first time I've beaten Nour, but it's also the first time that I’ve beaten the current world number one," Perry said.

Sarah-Jane Perry, left, beat Nour El Sherbini to claim a massive win ©PSA
Sarah-Jane Perry, left, beat Nour El Sherbini to claim a massive win ©PSA

Group A of the men's tournament also saw victory for Egypt's Marwan Elshorbagy who beat England's triple world champion Nick Matthew 11-13, 11-8, 11-7.

In Group B, France's world number one and defending champion Gregory Gaultier began with defeat, losing his 27-match unbeaten streak in the process.

He was shocked 11-5, 11-7 by Egypt's Ali Farag in under half-an-hour.

Marwan's brother Mohamed Elshorbagy, a former number one, made it a double for the siblings against English opponents by beating James Willstrop 11-8, 11-9 in the group's other game.

In Group A of the women's tournament, Nouran Gohar of Egypt beat her compatriot Raneem El Welily 13-11, 3-11, 11-3 to begin on a positive note.

France's top seed Camille Serme had to come from behind to beat England's Alison Waters 9-11, 11-5, 11-3.

In the other game in Group B, England's defending champion Laura Massaro began her campaign by defeating eight-time world champion Nicol David of Malaysia 12-10, 12-10.

Group play will continue tomorrow, with the top two players in each reaching the semi-finals.