Manager Jurgen Klopp said Liverpool overcame "the most defensive team I ever saw in my life" as they continued their fine form against Sunderland.
The Reds had 27 shots and 77.5% possession as goals from Divock Origi and James Milner earned a 2-0 win.
Klopp said that Sunderland striker Victor Anichebe played "left-back" as the Black Cats used "nine defenders".
"That's the most difficult thing in world football to come through," said Klopp. "But we worked for the moment."
Asked if the game compared in any way to Liverpool's goalless draw at Southampton last week, Klopp said: "I'm not sure I've ever played against a more defensive team than today.