Nodir Elibaev gave the Uzbeks a seventh-minute lead and Hurshid Tajibaev added a second three minutes later.
Khaled Takaji, who was sent off just before the end, reduced the deficit for Lebanon on 34 minutes but the Uzbeks had the last say with Dilshod Irsaliev scoring their third in the 40th minute.
Uzbekistan were favoured to win the game and enjoyed most of the possession in the early exchanges.
The Lebanese, facing a 2-0 half-time deficit, can out stronger after the interval and gave themselves hope with Takaji’s strike. But the home side recovered to put distance between themselves and their opponents with Irsaliev’s late goal.
Uzbekistan will be hoping to for another win against Indonesia in Group A on Monday, while Lebanon are out to bounce back against Chinese Taipei.