Grigoryev missed the 1976 season but reappeared in 1977 to win the Soviet title indoor and outdoors, as well as taking bronze medals at that year's Universiade and European Cup. His lifetime best jump of in Riga that June ranked him third in the world. He won the Soviet indoor title with an indoor best of , which was a championship record. He retained that outdoor title a year later and also broke the Soviet Athletics Championships record with outdoors. In international competition he placed fourth at the 1978 European Athletics Indoor Championships, but won the highest honour of his career at the 1978 European Athletics Championships – a silver medal behind Soviet teammate and world record holder Vladimir Yashchenko.