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 eventually transferred to Rapid București by coach Nicolae Roșculeț, where he made his Divizia A debut on 16 September 1962 in a 4–2 win against Farul Constanța. He stayed with Rapid for ten seasons, winning the title in the 1966–67 season, being utilized by coach Valentin Stănescu in 26 matches in which he scored one goal. Lupescu also won the 1971–72 Cupa României, two Balkans Cups and played all 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 that would eventually win the competition, Tottenham.