If it happens again try to find out if the noise is coming from the starter itself or the starter solenoid switch. A clicking noise can be caused by the solenoid making and breaking contact. This can be caused by bad screw contacts (loose or corroded leads or nuts) on the solenoid, a battery that is getting flat or on the way out or a faulty solenoid itself. All these need to be checked and fixed if needed and if the problem persists then the starter needs checking, although in my opinion I think that this is unlikely to be the problem.