The opening half-hour was competitive before Madrid were awarded a penalty -- minutes after they could have been given another for a shirt-pull on Rodrygo -- when defender Iza Carcelen fouled Vinicius Junior. Benzema scored it, then turned provider for Alvaro Odriozola to double Madrid's lead with a header, before scoring himself from Casemiro's cross to effectively end the contest.
The second half was uneventful, Madrid missing a series of chances to add to their lead, as Zinedine Zidane's side extended their unbeaten run to 16 games in all competitions.
For 90 minutes, the Super League uproar was momentarily forgotten. This win ended up being as comfortable as they come for Real Madrid after 10 glorious first-half minutes from Karim Benzema put the result beyond doubt. Benzema is a contender for La Liga player of the season, and he was operating at his fluid, commanding best here, a state of form exemplified by his movement and delivery for Odriozola's goal.
It was also encouraging to see the team work so well without both Toni Kroos and Luka Modric, two vital cogs in the midfield machine which has been essential to Madrid's on-field successes in recent weeks. Youngster Antonio Blanco -- who has no shortage of confidence -- looked comfortable filling in alongside Casemiro.
Cadiz's "Super League? Football is for everyone" T-shirts worn pre-match were an unwelcome reminder of the drama and embarrassment that have surrounded Real Madrid since Sunday night's news, as was the earlier hostile welcome from Cadiz fans on the team's arrival. On the pitch, though, there was really nothing to worry about here.
Manager rating out of 10
8 -- Zinedine Zidane welcomed Raphael Varane and Nacho Fernandez back into the squad and thus opted for a back three. That meant Marcelo and Alvaro Odriozola in wing-back roles, with Dani Carvajal only fit enough for a place on the bench. With Kroos and Modric missing, Blanco partnered Casemiro for his first start. All of those decisions paid off, as did pairing the two pacey Brazilians Vinicius and Rodrygo on either side of Benzema, before resting tired legs later.
Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)
GK Thibaut Courtois, 6 -- Real Madrid's player of the season was barely troubled here, with just one easy first-half save.
DF Eder Militao, 7 -- His reputation has been transformed this month. Could have done better with an early headed chance but otherwise did well.
DF Raphael Varane, 7 -- His first game back since testing positive for coronavirus. Picked up a bizarre first-half booking for blocking keeper Jeremias Ledesma's kick upfield.
DF Nacho Fernandez, 7 -- Brings leadership, experience and calm to the defence. Will be needed far more in the games to come. Missed a chance to score in added time.
DF Marcelo, 8 -- Captained the team and once again enjoyed himself at wing-back with plenty of cover behind him. Went close to scoring after half-time and was booked for a foul on Anthony Lozano.
MF Casemiro, 8 -- Even more responsibility on his shoulders without Kroos and Modric. Some loose passing early on, but picked out Benzema for Madrid's third.
MF Antonio Blanco, 8 -- A highly-rated midfield prospect for some time at youth level. Looked comfortable straight away, taking an early shot and playing one Kroos-esque crossfield ball for Marcelo, and worked hard off the ball.
FW Vinicius Junior, 7 -- A busy first half full of running and causing the Cadiz defence frequent problems.
FW Rodrygo, 7 -- Disappointing on Sunday but better here. Unlucky not to win a first-half penalty after showing great pace to beat Jairo. Confident enough to push Benzema away from a free kick which he put over the bar.
FW Karim Benzema, 9 -- Sensational. Scored from the penalty spot, set up Madrid's second with a superb piece of play, and scored again with a header, all inside 10 first-half minutes. He's up to 21 league goals now.
DF Dani Carvajal, 7 -- Back from his latest injury blow just in time for the final run in.
FW Marco Asensio, 6 -- Played on the left and was involved in one flowing late move.
MF Isco, 5 -- Didn't make much of an impact in half an hour on the pitch.
FW Mariano Diaz, N/R -- Missed the target after rounding Ledesma, but was offside in any case.
DF Miguel Ortega Gutierrez, N/R -- A first team debut for the gifted young left-back.