Real Madrid secured a 2-1 advantage over Atletico Madrid in the first leg of their Champions League last-16 tie on Tuesday night, setting up a finely balanced return leg next week.

Brahim Diaz scored the decisive goal 10 minutes into the second half, capping off a match that featured an open first half and a more cautious second period.

Real Madrid's Fede Valverde started at right back, with Diaz stepping in for the suspended Jude Bellingham. Atletico boss Diego Simeone opted for Antoine Griezmann and Julian Alvarez in his attack.

The hosts took an early lead in the third minute when Rodrygo latched onto a pass from Valverde, cut inside past Atletico left back Javi Galan, and curled a shot into the far corner past Jan Oblak.

Vinicius Jr had two chances to extend the lead, first seeing his shot blocked by Jose Gimenez and then shooting straight at Oblak after Real Madrid pressed successfully in midfield.

Atletico responded well, with Valverde showing his defensive skills to clear a dangerous cross from Giuliano Simeone with Samuel Lino lurking.

Julian Alvarez equalized for Atletico just after the half-hour mark, winning the ball on the left side of Real Madrid's penalty area, beating Eduardo Camavinga, and curling a stunning shot past Thibaut Courtois.

Atletico looked stronger in the second half, controlling possession and putting pressure on Real Madrid's defense. Rodrigo de Paul nearly put Atletico ahead with a shot from a narrow angle.

However, Real Madrid reclaimed the lead in the 54th minute through Diaz, who dribbled past two defenders and beat Oblak at his far post with a well-placed shot.

After Diaz's goal, Real Madrid maintained more control of the game, but both teams became more cautious, appearing content to avoid risks ahead of the return leg at the Metropolitano Stadium.