This study investigates the mechanism of global-scale magnetosphere convection driven by dayside magnetic reconnection. The Dungey cycle, which typically explains steady-state convection within the closed part of the magnetosphere through nightside reconnection, is challenged by time-dependent models suggesting that convection can be solely driven by dayside reconnection. The authors provide direct evidence supporting this alternative scenario through global simulations and observational data. They demonstrate that intensified magnetospheric convection and field-aligned currents (FAC) progress from the dayside to the nightside within 10-20 minutes following a southward turning of the interplanetary magnetic field (IMF). Observations reveal enhancements in both magnetosphere convection and the ionosphere's two-cell convection during this short timescale. The study highlights the importance of Region 1 and Region 2 FAC in the global-scale coupling of solar wind, magnetosphere, and ionosphere, and suggests that dayside reconnection and nightside reconnection act as independent drivers for magnetosphere convection. These findings have implications for understanding substorms and the upcoming Solar-Wind-Magnetosphere-Ionosphere Link Explorer (SMILE) mission.This study investigates the mechanism of global-scale magnetosphere convection driven by dayside magnetic reconnection. The Dungey cycle, which typically explains steady-state convection within the closed part of the magnetosphere through nightside reconnection, is challenged by time-dependent models suggesting that convection can be solely driven by dayside reconnection. The authors provide direct evidence supporting this alternative scenario through global simulations and observational data. They demonstrate that intensified magnetospheric convection and field-aligned currents (FAC) progress from the dayside to the nightside within 10-20 minutes following a southward turning of the interplanetary magnetic field (IMF). Observations reveal enhancements in both magnetosphere convection and the ionosphere's two-cell convection during this short timescale. The study highlights the importance of Region 1 and Region 2 FAC in the global-scale coupling of solar wind, magnetosphere, and ionosphere, and suggests that dayside reconnection and nightside reconnection act as independent drivers for magnetosphere convection. These findings have implications for understanding substorms and the upcoming Solar-Wind-Magnetosphere-Ionosphere Link Explorer (SMILE) mission.