It looked like they would hold on for victory, but Adebayor equalised with only 6 minutes remaining.
The two away goals would have given Arsenal the win, but the Reds weren't finished and Ryan Babel earned a penalty immediately after the restart.
Steven Gerrard converted to give Liverpool a 3-2 lead and Babel scored in the dying seconds to seal the game.
Benitez's side now face Chelsea once again in the semi-finals.
Talk about the game
