Manchester United and AC Milan needed 26 penalties to separate them in a shoot-out – with the Red Devils prevailing 9-8 after a 1-1 draw.
Alexis Sanchez's 12th-minute strike was cancelled out three minutes later as Manchester United beat the Italians in Carson, California.
The Chilean slotted a shot past Gianluigi Donnarumma to open the scoring in the International Champions Cup clash, but Suso drew the Serie A side level.
With the scores tied 1-1 after 90 minutes, United went on to win the penalty shootout 9-8 after 13 penalties each as Ander Herrera scored his second spot-kick while Franck Kessie sent his over the bar with an attempted Panenka.
Man United: Manchester United (3-4-2-1): Grant (J Pereira, 46); Smalling, Bailly, Tuanzebe; Darmian, Herrera, A Pereira, Shaw (Fosu-Mensah, 74), McTominay, Mata (Hamilton, 88); Sanchez