On his first competitive start for City since December 2008, the Brazilian scored for the first time for the club since September that same year to seal a comfortable win for the Blues in their Group A opener.
"To me, my players are the best in the world," said Mancini. "But I know for all strikers it is important to score goals. Jo has scored one important goal for us. Now I hope he continues to play in the same way."
Jo also created City's seventh-minute opener for David Silva, who put a difficult period behind him, stroking the Blues in front expertly from his team-mate's lay-off to cap an eye-catching performance that will silence the criticism that has started to grow around the Spain international.
"David is a fantastic player," proclaimed Mancini.
"But he is in a different situation now playing different football.
"After one month he is ready to go 100% for the team.
"He will also be an important player for the future."