Positional play can bring excellent positions.
However to finish off the game usually requires a tactical blow which will convert the advantage in a technical way. The name given to a series of tactical moves which may involve a sacrifice is a combination. For example if one has a passed pawn, there may be a tactical combination to forcefully queen it. If the opponents king safety is suspect, there may be a combination to checkmate. Tactical ability and the ability to spot combinations thus helps to convert positional advantages into more concrete gains.