I giorni contati (1962), was his second film, again co-authored with Tonino Guerra. After two somewhat lesser films Il Maestro di Vigevano, (1963) and the Sketch Sin in the afternoon, included in High Infidelity, 1964, Petri directed The 10th Victim (1965), a film with Futuristic overtones also co-authored with Tonino Guerra. In 1967, he shot We Still Kill the Old Way (adapted from the novel To Each His Own by Leonardo Sciascia), dealing with the individual's inability to cope with reality. The film also the beginning of the collaboration with the script-writer Ugo Pirro which was to last until 1973.