Robert Blair and Imogen Bankier have been under the weather like a wet and windy morning in the highlands under the past fortnight.

But the Scottish-born mixed doubles pairing have found the Yonex All England Open Championship in Birmingham like the perfect summer's day after following the best win of their fledgling career with another top 20 scalp yesterday.

After surviving a late night encounter on Wednesday to defeat world No 3 Flandy Limpele and Vita Marissa, Blair and Bankier booked their place in this evening's quarterfinals place with a surprisingly easy win over world No 19 pair Chen Hung Ling and Chou Chia Chi.

The Chinese pair were brushed aside 21-14, 21-12 to earn an all-British last-eight clash with eighth seeds Nathan Robertson and Gail Emms.

"I definitely feel we have a chance," said Bankier. "We played them in the French Open and it was a close game though they lost in two sets."

Robertson and Emms, the 2005 champions and 2006 runners-up, were last on court last night but held their nerve to defeat Koreans Hwang Ji Ma and Kim Min Jung 21-17 21-17.

Home fans were already guaranteed another English pair to support in the mixed doubles after Anthony Clark and Donna Kellogg progressed to the last eight.

The pair, beaten finalists last year, swept aside seventh seeds Sudket Prapakamol and Saralee Thoungthongkam. They defeated the Thai pair 21-11, 21-16 in 33 minutes and now face fourth seeds Xie Zhongbo and Zhang Yawen from China.

Bankier and Blair had to pull out of last week's Yonex German Open because Bankier was ill, while Blair is still suffering from a flu bug which meant he was on his phone to the team doctor within minutes of their victory yesterday. But their Chinese Taipei rivals never had a sniff of overturning the Scottish Open champions.

"After such a great result on Wednesday, it would have been a shame if we had gone out in the next round," said Glasgow-born Bankier. "We were determined to get through."

Blair added: "We played a very controlled game and our style worked very well against them.

"It's a big achievement to get to the quarter-finals in a tournament like this. It's the best in the world and to get this far you know you have to beat some very good pairs."

The partnership has only been together for the past ten months and there's a hint of disappointment that the pair who have risen to No 31 in the world rankings are likely to run out of time in the race for the Olympic Games.

They are currently Britain's fourth-ranked pair, having teamed up when Bankier moved to train in Milton Keynes.

Blair, who hails from Edinburgh but then moved to Loughborough University and now represents England, added: "Imogen came down because it is the British base for the Olympic squad. I wasn't playing any mixed doubles so it was suggested I played with Imogen over in a tournament in the Far East and I thought we could develop a good partnership.

"If we had started playing together a little bit earlier we might have had a good chance to get to the Olympics. Nathan and Gail are doing well but I think we could have challenged Anthony and Donna."