Ponomaryov was dominant nationally in 1977, taking the 800 m indoor title and an 800/1500 metres double at the Soviet Championships. He was absent in the 1978 season but returned the following year to win his last national titles over 1500 m at the Soviet Indoor Championships and Spartakiad. In his last major international outing, he took his highest honour – a 1500 m silver medal at the 1979 IAAF World Cup behind West Germany's Thomas Wessinghage. He set a lifetime best of 3:37.9 minutes for the event that same year.