Sergio Ramos, Carlos Sainz watch Carlos Alcaraz dismantle Alexander Zverev at Madrid Open

Defending champion Carlos Alcaraz booked his spot in the quarterfinals of the 2023 Madrid Open with a 6-1, 6-2 demolition of Alexander Zverev on Tuesday.

In a repeat of last year's final, Alcaraz dropped one game fewer against the German this time around. He barely put a foot wrong as he closed out the contest in an hour and 22 minutes.

Along with hundreds of excited fans in Madrid, the Spanish hope was also cheered on by two of the biggest sporting heroes in the country's history -- footballer Sergio Ramos and F1 racer Carlos Sainz.

The best defender in the house today...

¡Hola, @SergioRamos! 👋⚽️

#MMOpen https://t.co/LHhfsnuVdT

Ramos, who represented Alcaraz's favorite football club Real Madrid for more than 15 years, and Sainz, who currently races for F1 giants Ferrari, got a front-row ticket to see the World No. 2 at his belligerent best. Having already defended his first career title at the Barcelona Open before coming to Madrid, Carlos Alcaraz will be hoping to defend his first Masters 1000 title this week.

🚙🏁 @CSainz_oficial

#MMOpen https://t.co/Iv2yn4t8TE

Carlos Alcaraz takes on Karen Khachanov in Madrid Open quarterfinals

Following his victory over Alexander Zverev, Carlos Alcaraz will take on 10th seed Karen Khachanov in the quarterfinals of the 2023 Madrid Open. Khachanov beat compatriot and reigning Monte-Carlo champion Andrey Rublev in the fourth round to set up a meeting with the Spaniard.

The duo have met twice on the ATP Tour previously, with both meetings going in favor of Alcaraz. Interestingly, both encounters came on clay (at the 2022 Hamburg European Open and 2022 French Open), and the teenager is yet to drop a set against his veteran opponent.

Speaking to the press after his victory over Zverev, the Spaniard remarked that he was "very happy" with the level he displayed on the night and was looking forward to carrying the momentum onto the next round.

"Well, obviously Sascha, it wasn't his best match, but, well, I didn't expect that win. But obviously I played a great match. I didn't let him play his game. All I can say is I play my best level, and I'm really, really happy with the level that I played today," Carlos Alcaraz said.

A victory against Karen Khachanov would pit the top seed against either 17th seed Borna Coric or Daniel Altmaeir in the semifinals. Fourth seed Stefanos Tsitsipas remains the favorite to reach the final from the bottom half of the draw in Madrid.