The Denmark centre-back scored the first in the 2-0 win over Hull, with Luis Suarez netting the second with a now trademark free-kick to take his tally to 20 in 15 matches, becoming the fastest player in Premier League history to achieve the feat.
It was far from their best or most fluid performance, but after back-to-back defeats had seen them fall from first to fifth a victory was all that was required to get Liverpool back on track.
"The most important thing was three points, it is as simple as that," Agger told LFC TV.
"It was not our best performance, but if we can win and get three points without playing our best that is important in the long run.
"Not only was it important for confidence but also just to stay in the top (four).
"That is so important to hang in there and we have done that."
The clean sheet was only the Reds' third in the last 18 matches.
But manager Brendan Rodgers, who racked up his 100th point in charge at Anfield, was grateful to Agger, who was the only one to convert a number of chances in the first half, and Suarez for securing victory.
"Of course you don't want to concede soft goals and thankfully we didn't," he said.
"We worked tirelessly to stop them getting anything - they had no shots on target.
"Clean sheets are important, but there's no good having 15 clean sheets if you can't score so it's about getting the balance in the team.
"But the most important thing is the victory and the goals and we got that."
Hull boss Steve Bruce felt the packed festive programme finally caught up with his side.
"Towards the end we were game enough to keep trying, but you could see a lot of tired bodies and the third game in six days was a bit too much for us," he said.
"It was a big ask for us, we needed to be right at it and be fresh and it was a bit too much for us.
"A footballer can play a match every day but he can't play with the same intensity.
"We looked tired towards the end, your concentration goes and you don't have the energy to compete.
"Sometimes you have to say you were beaten by the better team and we were.
"The disappointing thing is the game was settled by two set-pieces. Luis Suarez's free-kick has made the game comfortable for them in the end."