During this period, Stean frequently had to put aside his own playing ambitions, as he was engaged as one of Viktor Korchnoi's team of seconds for world championship campaigns in 1977-78 and 1980-81. In many respects, the partnerships that developed were reasonably successful; Korchnoi brushed aside some powerful rival Candidates like Boris Spassky, Robert Hübner and Lev Polugaevsky en route to his two finals with Karpov. Stean's role was mostly involved with opening preparation and he and Korchnoi became good friends.