The Dutchman plundered 15 goals in all competitions, including scoring in five successive league games and netting a hat-trick against Manchester United.
"Sometimes his work goes unnoticed but we as players always appreciate the shifts he puts in," Gerrard told LFC Weekly.
"Dirk and Luis particularly were very influential towards the end of last season - mainly because both players work unselfishly for the team. The pair of them don't give defenders a moment's rest.
"When you do see them working like that, it encourages the team to do the same - defending from the front."