U.S. Clay Court Championships in July, Burwash lost in the first round, to Terry Addison, 2–6, 3–6. He played one main draw in doubles, at the U.S. Open, again with partner Rudy Hernando, and lost by default to Roy Emerson and Rod Laver. 1971 Burwash competed in main draws at two major events, the Canadian Open and the U.S. Open. In Montreal, he lost to Ismail El Shafei 3–6, 4–6 in singles, and partnering compatriot Ken Binns, lost to Bob Lutz and Charlie Pasarell in doubles. At Forest Hills, he was beaten by Milan Holeček, 1–6, 0–6, 7–5, 4–6. Burwash won the Canadian National Championships singles (closed) defeating Jim Boyce in the final and thereby gaining the Canadian No. 1 ranking for that year. Burwash won the third annual Omnium de Tennis Labatt du Québec or Quebec Open played at the Club de Tennis des Loisirs de Granby defeating Rudy Hernando of Detroit in the final 2–6, 6–1, 6–3. 1972 Burwash participated in the main draw in both singles and doubles at the Columbus Outdoor, losing to Charles Owens. In doubles he also lost in the first round, partnering Ian Fletcher. A week later at the U.S. Clay Court Championships, Burwash lost 1–6, 1–6 to Toshiro Sakai. In doubles, he and partner William Higgins lost 2–6, 2–6 to Jim Delaney and James Chico Hagey. The following week at the Canadian Open, his last appearance there in a main draw, Burwash lost to Jaime Fillol 6–7, 2–6, after a bye in the first round. 1973 Burwash was entered in the main draw of two grand prix events. At the Calgary Indoor, held in February, he lost in the first round to Nicholas Kalogeropoulos 4–6, 3–6. In doubles Burwash partnered Franklin Robbins and lost in the first round as well. In August, Burwash was set to play John Newcombe in the first round of the Louisville Outdoor but defaulted. 1974 Burwash lost by default to Bob Giltinan in the first round of the Calgary Indoor in what would be his last tour result. The computer rankings having been introduced only in September 1973, Burwash received his highest singles ranking in June 1974, when he was ranked World No. 240. He never earned a doubles ranking, as they were not kept until 1978. After tennis tour playing days After retiring from professional tennis in 1975, he founded a tennis management company. Burwash was