Beginning in 1962, Portisch became a consistent tournament winner at the international level. He shared the title at Sarajevo 1962 with Svetozar Gligorić on 8/11. He shared second/third places at Kecskemét 1962 on 10½/15 behind Ratmir Kholmov. Portisch won Amsterdam IBM 1963 with 6/9 ahead of Jan Hein Donner. He won Sarajevo 1963 with 7/11, ahead of Gligoric, Vladimir Simagin, Wolfgang Uhlmann, and Borislav Ivkov. At Havana 1964, he scored 14/21 for fifth place as Uhlmann and Smyslov won. At Beverwijk 1964, he was third with 11/15 behind Paul Keres and Iivo Nei. He shared second/third at Málaga 1964 on 7½/11 behind Arturo Pomar. He shared the title at Beverwijk 1965 on 10½/15 with Geller. At Yerevan 1965, he was fifth with 7/13 as Korchnoi won. With six of the world's top 25 in the field at Zagreb 1965, Portisch scored 12/19 for a shared third/fourth place, as Borislav Ivkov and Uhlmann won. He was third at Mar del Plata 1966 on 9½/15, with Smyslov winning. Portisch shared the title at Kecskemét 1966 on 6½/9, along with Vlastimil Hort. At Santa Monica 1966, with seven of the world's top 16 players in the field, he shared fourth/fifth places on 9½/18, as Spassky won, ahead of Fischer. Portisch was third at Palma de Mallorca 1966 on 10/15, with Tal winning.
