REAL Madrid manager Carlo Ancelotti was pleased with his side's resilience as they earned a 2-1 win over Atletico Madrid at the Bernabeu in the hard-fought first leg of their Champions League Round of 16 tie on Tuesday.

Brahim Diaz scored the second-half winner after Atletico forward Julian Alvarez had cancelled out Rodrygo's opener.

Vinicius Jr and Kylian Mbappe both missed good chances that could have given Real a bigger margin for the second leg but Ancelotti was not in the mood to lament missed opportunities.

He preferred to stick with the positive which is a win against what he considers one of Europe's best teams this season and said his players will need even more effort to make the most of their narrow advantage to advance in their title defence.

"These are evenly matched games. It's a Round of 16 in the Champions League as it could be a final or a semi-final. Atletico are a top team in Europe and you can't think about finishing the tie in the first leg," Ancelotti told a press conference.

"We've gained a small advantage that gives us confidence for the second leg but that's it. It was a difficult match ... as usual. It always is against Atleti.

"In the first half we lost too many balls, we had unnecessary mistakes that almost cost us, they levelled the game with Julian Alvarez. But in the second half we were better. We were able to take advantage and we did it."

Ancelotti downplayed what seemed to be a disappointing night for Mbappe and Vinicius, praising the work of Atletico's defence in neutralising his pair of world-class attackers.

"I think playing against Atletico's defence is not that easy a task," Ancelotti said. "We haven't had many chances throughout the match and the two of them have worked hard, they've fought hard...

"They haven't had the chance to show the quality we all know they have but they've got the return leg to do it."

The winners of the tie will surely meet Arsenal, who are in a virtually unassailable position to reach the quarter-finals after a 7-1 victory at PSV Eindhoven in Tuesday's first leg.

Meanwhile, Atletico Madrid manager Diego Simeone was disappointed that his side failed to capitalise on the control they had for long periods of their 2-1 defeat to rivals Real Madrid in the first leg of their Champions League last-16 tie on Tuesday.

But Simeone said he was happy with how his team reacted to conceding an early goal, adding that he felt confident they could turn the tie around in the second leg at the Metropolitano stadium next week, as they did against Inter Milan at the same stage last year.

"We should have taken better advantage when we had control of the game," Simeone said.

"It's difficult to take risks so that with any counter-attack you end up losing the game. We controlled that situation very well, but we were missing (something) in the final metres."

The Argentine said he was confident that the atmosphere at their home ground would give Atletico "a stimulus" and that while his team go into the second leg behind, it could have been much worse had Real taken a late chance on Tuesday.

Real's Kylian Mbappe failed to find Vinicius Jr with a pass in the final moments of the match that could have led to another goal.

"Maybe the hope of that no goal opens the door for what's to come," he said.