press home (one's) advantage

To capitalize on or make full use of the advantage one has. With the party in disarray following the resignations of several top members, the opposition is looking to press home their advantage in the upcoming elections.

press ˌhome your adˈvantage

make good use of the fact that you are in a stronger position than your opponent, enemy, etc: Once they realized that the management was so weak, the union leaders pressed home their advantage and asked for another three days’ holiday.