City remain in 5th, one point behind 4th-placed Liverpool, which is their highest position at New Year in the Premier League.
Dunney has been City's Player of the Year for the last 3 seasons and Sven believes he and defensive partner Micah Richards have provided the foundation for City's fine first half of the campaign.
"I thought Richard was colossal," said Sven. "He had a magnificent game, absolutely outstanding. The entire back four were superb and I thought we deserved the point.
"Richard and Micah have been so important for us this season. It's like building a house, you start from behind and they have done an excellent job for us all season."
Sven felt the festive programme had begun to get the better of City in the closing stages so was relieved to hang on.
"We tired at the end and that affected us," he said. "We had one day less between this game and the last (2-2 against Blackburn), but a point and a clean sheet against a team like Liverpool has to be a good result for us."