Jose Mourinho's men came from a goal down to put Manolo Jimenez's men to the sword at home, with the three attackers all getting on the scoresheet in the 3-1 victory
Angel Lafita gave the visitors a shock lead on 11 minutes after some slack defensive play from Los Blancos, yet Kaka got his side back on level terms in the 32nd minute.
The home side were 2-1 up not long after the break when Ronaldo scored from close range before Ozil completed the scoring with a powerful finish in the area.
Mourinho's side head eight points clear of rivals Barcelona who visit Villarreal later in the evening while Zaragoza remain bottom after extending their winless run in the league to 13 games.
Madrid forged the first opportunity of the game in the sixth minute when Cristiano Ronaldo's precise cross into the box was inexplicably headed wide of goal from four yards out by Karim Benzema.
Despite their bright start to the game, Madrid found themselves a goal down five minutes later after some poor defending. Carlos Aranda was allowed time and space to make a run into the box before the forward played a low ball along the six-yard line for Angel Lafita to tap into an empty net - his third goal at the Santiago Bernabeu after his double last season.
In the 26th minute, Mourinho's men came close to an equaliser from a set-piece. Mesut Ozil whipped an inviting ball into the box which was met by Kaka's flicked header that narrowly crept wide of the top corner with Roberto at full stretch.
However, the home side did not have to wait long to draw back level and on 32 minutes, the goal arrived. Ricardo Carvalho's defensive-splitting pass fell to the feet of Kaka who took a composed touch before stroking the ball into the net, despite Roberto's best attempts at keeping it out.
A determined Madrid side came out for the second half and in the 49th minute the hosts grabbed the lead. After a slick passing move, Esteban Granero slid the ball to Ozil who cut the back across the six-yard line for Ronaldo to slam home - a goal reminiscent of Zaragoza's opener.
Seven minutes later Mourinho's team extended their lead with another well-executed team goal. Granero and Kaka both linked up impressively before the Brazilian found Ozil in the box, who smashed the ball past Roberto at his near post for the German's first league goal of the season and the final goal of the game.
Madrid are back in Liga action next weekend when they travel to local rivals Getafe while Zaragoza are due to entertain Rayo Vallecano.