As a specialist opening batsman, Sutcliffe's rivals on the field were the opposing bowlers and especially fast bowlers, though he encountered many outstanding spin bowlers too on turning or sticky wickets.  By the time Sutcliffe began his Test career, the formidable fast bowling partnership of Jack Gregory and Ted McDonald had ended, though Sutcliffe faced Gregory in Test matches and was opposed to McDonald in "Roses matches" between Yorkshire and Lancashire. Gregory by 1924-25 was no longer able to "frighten batsmen with sheer speed" but he still commanded respect and Jack Hobbs specifically told Sutcliffe to exercise caution against Gregory at the start of an innings. Sutcliffe regarded McDonald as "one of the best bowlers I ever met". He commented on McDonald's trick of "resting" by making himself seem tired and then "hurling himself into (a very fast delivery) like a demon". As Sutcliffe said, he never knew which ball would be the fast one and McDonald was a dangerous opponent.  But Sutcliffe was quoted as saying that he had "never played finer fast bowling" than that of the West Indians Learie Constantine, George Francis, Herman Griffith and Manny Martindale. Among the best English bowlers he faced in county cricket were some of his colleagues in England teams, such as Harold Larwood, Maurice Tate and Tich Freeman.  One of the toughest competitors he faced was the Australian leg spinner Clarrie Grimmett, "a tiny gnome of a man", who bowled with a roundarm action and made his Test debut at the age of 34, taking 11 wickets in his first match. Grimmett bowled "like a miser" and "begrudged every run", whereas his leg spin partner Arthur Mailey was the type of bowler who would "buy" his wickets by conceding runs and then, having boosted the batsman's confidence, snaring him with a "wrong 'un" (i.e., a googly). On Sutcliffe's first tour of Australia, he commented that he "was troubled most of the time by Arthur Mailey" but eventually he learned how to "differentiate between Mailey's leg breaks and his wrong 'uns".

Answer this question "Why were they noted opponents of him?" by extracting the answer from the text above.
the formidable fast bowling partnership