He was eventually brought to Rapid București by coach Nicolae Roșculeț where he debuted in Divizia A on 16 September 1962 in a 4–2 victory against Farul Constanța. He remained with Rapid for ten seasons, winning the title in the 1966–67 season, being used by coach Valentin Stănescu in 26 matches in which he scored one goal. Lupescu also won the 1971–72 Cupa României, two Balkans Cup and played all the six games in the 1971–72 UEFA Cup campaign, as the team reached the eight-finals, eliminating Napoli and Legia Warsaw, being eliminated by the team who would eventually win the competition, Tottenham.
He was later taken to Rapid București by coach Nicolae Roșculeț, where he made his first Divizia A appearance on 16 September 1962 in a 4–2 victory over Farul Constanța. He remained with Rapid for ten years, winning the championship in the 1966–67 season under coach Valentin Stănescu, scoring one goal in 26 matches. Lupescu also won the 1971–72 Cupa României, two Balkans Cups, and played all six games in the 1971–72 UEFA Cup campaign, where Rapid reached the eight-finals, defeating Napoli and Legia Warsaw before being eliminated by Tottenham.