ATHENS - Inter made the perfect start to their 2008/09 Champions League campaign with a 2-0 victory over Panathinaikos.
Mancini opened the scoring in the 27th minute of Tuesday's Group B opener, slotting beyond Galinovic after Ibrahimovic juggled the ball past two opponents.
Second-half sub Adriano made sure of the points after replacing Mancini, crashing home his shot from Ibrahimovic's delightful through ball with five minutes remaining.
José Mourinho named a 4-3-3 lineup at the Olympic Stadium, starting with Quaresma, Ibrahimovic and Mancini in attack with a midfield line of Vieira, Cambiasso and Zanetti.
The Nerazzurri stepped up a gear after an early period of Panathinaikos pressure and Ibrahimovic slid wide from Vieira's inviting pass into the area.
Galinovic was forced into saves from Quaresma and Ibrahimovic as Inter imposed their domination before Mancini broke the deadlock.
Ten Cate's men could have equalised within minutes but the ever dependable Julio Cesar produced a tipped save from Bryce Moon's long-range effort.
The South African went close again minutes before the break, his shot from the edge of the box taking a deflection off Materazzi before coming back off the crossbar.
Ivanchitz, Cleyton and Salpingidis carved out chances as Greeks made an aggressive start to the second period, prompting Mourinho to shuffle his pack and introduce Figo and Muntari for Quaresma and Vieira.
Panathinaikos continued to press and Julio Cesar was kept busy, with Inter limited to counter-attacks.
Mourinho made his third change in the 82nd minute, and it proved to be the turning point.
Three minutes after replacing Mancini, Adriano celebrated with a goal his first competitive appearance for Inter since last October's Serie A visit to Reggina.
Panathinaikos 0-2 Inter (HT: 0-1)
Scorers: Mancini 27, Adriano 85.
Panathinaikos: 1 Galinovic; 24 Vintra, 23 Simao, 8 Goumas, 29 Nillson (17 Hristodoupoulos 72); 2 Moon (9 Souza 82), 15 Gilberto Silva, 4 Mattos; 10 Cleyton, 14 Salpingidis, 21 Karagounis (27 Ivanchitz 37).
Subs not used: 30 Tzorvas, 3 Sarriegi, 2 Tziolis, 31 Spyropoulos.
Coach: Henk Ten Cate.
Inter: 12 Julio Cesar; 13 Maicon, 2 Cordoba, 23 Materazzi, 6 Maxwell; 14 Vieira (20 Muntari 62), 19 Cambiasso, 4 Zanetti; 77 Quaresma (7 Figo 64), 8 Ibrahimovic, 33 Mancini (10 Adriano 82).
Subs not used: 1 Toldo, 9 Cruz, 39 Santon, 45 Balotelli.
Coach: José Mourinho.
Referee: Mejuto Gonzalez (Spain).
Booked: Materazzi 22, Cleyton 33, Maicon 46.