Ouseph, who had beaten Du in straight games at the Hong Kong Open in November in their only previous meeting, progressed to the second round in the West Midlands 21-16, 11-21, 21-14.
He has now earned a second-round clash with Japan's Kento Momota, who is ranked seven places higher than the London 2012 Olympian man at 15 in the world and was the world junior champion two years ago.
Ouseph said: "I think it shows that on my day I'm up there with the best in the world, he was top ten so for me to win shows that I can play at that level, and I hope I can maintain it."
Meanwhile, Chris Adcock enjoyed a memorable day in Birmingham as he safely navigated first round games in both the men's doubles and mixed doubles.
Adcock and his partner Andrew Ellis, who are ranked as the number eight seeds in the West Midlands, defeated Jui Wei Liang and Kuan Hao Liao from Chinese Taipei 18-21, 21-13, 22-20 to set-up a second round clash with China's Haifeng Fu and Nan Zhang.
While in the mixed doubles Adcock, who is playing alongside his wife Gabby, defeated Indonesian duo of Irfan Fadhilah and Weni Anggraini 21-9, 17-21, 21-14 and will play Germans Peter Kaesbauer and Isabel Herttrich next.
And speaking after his mixed doubles performance Chris Adcock said: "It's great for the crowd to see this kind of badminton and us winning obviously helps a lot.
"The crowd were great and helped us out again in the third; the volume went up when we were winning so they pushed us along.
"I don't think it's a massive ask for us because I know if we play well we can go a long way and do some real damage at this tournament.
"There are good players every round so I think we've got a tough match against the German pair next but we'll just take it a game at a time and hopefully if we can get to the quarters then we'll give it our all."
© Sportsbeat 2014
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- Chris Adcock