Nielsen, who benefited from an England protest against a re-draw, won 15-10, 15-6 against his Danish namesake, Soren Nielsen, his conquerer in last month's All-England Championships, and then 15-10, 15-5 against Thomas Mendrek, of the Czech Republic.
This put the England No 2 in the top place of the quarter- finals, which would almost certainly have been occupied by the top-seeded Thomas Stuer- Lauridsen had he not withdrawn injured. Nielsen's opponent today is the Dutch No 1, Jeroen van Dijk, whom Nielsen beat two years ago in Glasgow.
The England No 1, Joanne Muggeridge, also advanced to the last eight by beating Georgy Trouerbach, of the Netherlands, and Anne Gibson, of Scotland, earning herself a meeting today with the defending European champion from Denmark, Pernille Nedergaard.
However, there was disappointment for England in the women's singles when the national champion, Suzanne Louis-Lane, failed to reach her seeded place. A tired performance saw Louis-Lane beaten in the second round, 11-6, 11-4 by Denmark's Anne Sondergaard.