Serhou Guirassy struck twice for the German outfit as they scraped past Sergio Ramos's side 2-1 in a tight last-16 clash in Atlanta and denied the former Real Madrid skipper a match-up against his former team.

Youngster Gonzalo Garcia headed home his third goal of the tournament to help Madrid edge Italian side Juventus at the Hard Rock Stadium in Miami earlier.

It was an impressive display from Xabi Alonso's Madrid side, unbeaten under the new coach, and they were further boosted by Kylian Mbappe's return from illness as a substitute.

"We had a lot of chances in the second half, but their goalkeeper was really good," said Madrid shot-stopper Thibaut Courtois.

The first half was a finely-balanced contest with Igor Tudor's Juventus starting brightly before Real ended it on top.

Los Blancos kept turning the screw and found their goal when Trent Alexander-Arnold crossed for Gonzalo to head home after 54 minutes.

Alonso decided to introduce Mbappe to the delight of the 62,149 crowd but the striker did not find any clear openings as Juve pushed for an equaliser.

Madrid's coach was pleased with his team's performance, including that of Gonzalo -- who he had compared to former Real great Raul -- but also suggested that Mbappe might be ready for a bigger contribution in the next game.

"We will keep watching him... I think he will be much better for the quarters," Alonso said.

Alonso added that he was satisfied to see Real produce the necessary grit to grind out the result in the second half.

"We had to be patient, we had to mature into the game," said the coach.

"With the players and myself, you know you have to grit your teeth and do what you have to do. And in the end, we had to hold on a bit, and I'm happy about that too."

Juve boss Tudor said his team became exhausted as the game developed.

"In the end there were 10 of them asking to be substituted. Obviously you can't do that but there was an incredible tiredness," he said, offering his reasons.

"There is the tension of the game which burns energy but then there is the heat and humidity," explained Tudor, also noting they were at the end of a long season.

- Dortmund deny Ramos -

In Atlanta, Guirassy's brace was enough to help Dortmund past Monterrey in a hard-fought clash, setting them up to play a Madrid side who beat them in the 2024 Champions League final.

"Real has a great team, they have many good individual players," Dortmund coach Niko Kovac told reporters.

"If we put everything on the pitch, (giving) the same performance as we saw today, I think that we will have a good chance."

Guirassy netted a first-half double but German Berterame pulled one back for the Mexican side who came close to an equaliser when a late Ramos header span just wide.

"I think I could have scored at least three goals but I am happy to have helped the team win," Guirassy told broadcaster DAZN.

After grinding through several games in the blazing afternoon sun during the group stage, Dortmund were grateful to be at the air-conditioned Mercedes-Benz Stadium and played at a faster pace in Atlanta.

Karim Adeyemi set up both of Guirassy's goals as the Guinea international reached 37 for the season across all competitions.

A booking for Jobe Bellingham means he will be suspended for the clash against his brother Jude's Real Madrid side.

However Dortmund almost missed out entirely as Monterrey hit back in the second half, but after Berterame headed home to reduce the gap, goalkeeper Gregor Kobel made several good saves to keep them at bay.

Ramos, sent up front for the final stages, put a header agonisingly wide in stoppage time as he tried to deliver on his penchant for late, decisive moments, like in Madrid's 2014 Champions League final triumph.

"The crowd and our fans and the people who understand about football, they saw that the team gave everything," Ramos told DAZN, proud of his side's efforts.