A method of drilling a subsea wellbore, comprising: drilling the subsea wellbore by: injecting drilling fluid through a tubular string extending into the wellbore from an offshore drilling unit, ODU; and rotating a drill bit disposed on a bottom of the tubular string, wherein: the drilling fluid exits the drill bit and carries cuttings from the drill bit, the drilling fluid and cuttings (returns) flow to a subsea wellhead via an annulus defined by an outer surface of the tubular string and an inner surface of the wellbore, and the returns flow from the subsea wellhead to the ODU via a marine riser; characterized by, while drilling the subsea wellbore: measuring a flow rate of the drilling fluid injected into the tubular string; measuring a flow rate of the returns; comparing the returns flow rate to the drilling fluid flow rate to detect a kick by a formation (104u,b) being drilled; and exerting backpressure on the returns using a first variable choke valve; and in response to detecting the kick: closing a blowout preventer (42a,u,b) of a subsea pressure control assembly, PCA, against the tubular string; and diverting the flow of returns from the PCA, through a choke line having a second variable choke valve, and through the first variable choke valve. drilling the subsea wellbore by: injecting drilling fluid through a tubular string extending into the wellbore from an offshore drilling unit, ODU; and rotating a drill bit disposed on a bottom of the tubular string, wherein: the drilling fluid exits the drill bit and carries cuttings from the drill bit, the drilling fluid and cuttings (returns) flow to a subsea wellhead via an annulus defined by an outer surface of the tubular string and an inner surface of the wellbore, and the returns flow from the subsea wellhead to the ODU via a marine riser; injecting drilling fluid through a tubular string extending into the wellbore from an offshore drilling unit, ODU; and rotating a drill bit disposed on a bottom of the tubular string, wherein: the drilling fluid exits the drill bit and carries cuttings from the drill bit, the drilling fluid and cuttings (returns) flow to a subsea wellhead via an annulus defined by an outer surface of the tubular string and an inner surface of the wellbore, and the returns flow from the subsea wellhead to the ODU via a marine riser; the drilling fluid exits the drill bit and carries cuttings from the drill bit, the drilling fluid and cuttings (returns) flow to a subsea wellhead via an annulus defined by an outer surface of the tubular string and an inner surface of the wellbore, and the returns flow from the subsea wellhead to the ODU via a marine riser; characterized by, while drilling the subsea wellbore: measuring a flow rate of the drilling fluid injected into the tubular string; measuring a flow rate of the returns; comparing the returns flow rate to the drilling fluid flow rate to detect a kick by a formation (104u,b) being drilled; and exerting backpressure on the returns using a first variable choke valve; and measuring a flow rate of the drilling fluid injected into the tubular string; measuring a flow rate of the returns; comparing the returns flow rate to the drilling fluid flow rate to detect a kick by a formation (104u,b) being drilled; and exerting backpressure on the returns using a first variable choke valve; and in response to detecting the kick: closing a blowout preventer (42a,u,b) of a subsea pressure control assembly, PCA, against the tubular string; and diverting the flow of returns from the PCA, through a choke line having a second variable choke valve, and through the first variable choke valve. closing a blowout preventer (42a,u,b) of a subsea pressure control assembly, PCA, against the tubular string; and diverting the flow of returns from the PCA, through a choke line having a second variable choke valve, and through the first variable choke valve.