The 21-year-old joined the Stags on trial at the beginning of the week.
But Pacquette convinced Curle of his quality after finding the back of the net in the Stags' 3-0 friendly win over Crewe, where Craig Disley and Lee Williamson were also on target for the hosts.
Pacquette will go straight into the Mansfield squad which travels to Rochdale on Saturday.