Okazaki celebrated his first start since September 10 by scoring the second goal in a 3-1 defeat of Crystal Palace
The Premier League champions ended a three-game winless run last weekend by beating Crystal Palace 3-1 and Okazaki celebrated his first start since September 10 by scoring the second goal.
The hard-working forward, 30, helped set the tempo for Leicester's display and Ranieri used his famous rallying cry from last season's 5,000-1 title triumph to highlight Okazaki's importance.
"He is a hard worker. Sometimes he's not so close to goal, but when the ball is around the box Shinji is always there," said Ranieri, whose side visit Tottenham Hotspur on Saturday.
"He is important for the team because he presses a lot. He is our 'dilly ding, dilly dong'. He wakes up our players -- he has the bell!"
While Okazaki's goal against Palace was his first of the campaign, his overall display illustrated his worth to Ranieri's side.
The Japan international covered 11.66 kilometres (7.25 miles) during the game -- more than a kilometre more than fellow strikers Jamie Vardy and Islam Slimani in any game this season.