Harris, 29, now faces Paul Johnson, hoping to avenge the 3-2 defeat by the England No 1 in the last 16 of the World Open in December in Qatar.
The British champion and eighth seed Simon Parke squandered a two-game lead for the second successive round before overcoming Irish champion Derek Ryan 15-5, 15-12, 12-15, 11-15, 15-5 in 70 minutes. He now meets world No 1 Peter Nicol, who dismissed the Welsh champion David Evans 15- 10 ,15-5, 15-6.
Australia's Byron Davis caused the first seeding upset of the day, twice coming back from behind to defeat Scotland's world No 6, Martin Heath, 15-17, 15-10, 8-15, 15-13, 15-2. Heath, the fifth seed, said afterwards: "I never liked the court, or perhaps the new yellow ball is heavier - it comes fast off the wall and then stops. I never got into a rhythm,"
Davis, 25, the world No 19 from Adelaide, now faces Canada's third seed Jonathon Power, the world No 2 from Toronto who comfortably beat the South African qualifier, Rodney Durbach, 15-8, 15-4, 15-9.