A late Diego Costa header earned Club Atlético de Madrid a 1-0 win at AC Milan but the Spanish side also had goalkeeper Thibaut Courtois and a portion of luck to thank for their first-leg lead in this round of 16 tie.
With Clarence Seedorf making his coaching debut in a competition he won four times as a player, the Rossoneri were twice denied by the woodwork in a fluent first half, with Courtois getting a crucial touch both times. Openings were harder to come by in the second period but Atlético never really looked like scoring until Diego Costa swooped seven minutes from time, his fifth goal in four UEFA Champions League games this season.
Diego Simeone's team began positively enough, forcing Milan onto the back foot, but the pendulum quickly swung the other way. Kaká was responsible, curling a powerful 14th-minute shot from the right edge of the box onto the crossbar via Courtois' glove. The home fans roared and grew louder still soon after when Andrea Poli met Adel Taraabt's cross from the right with a header which seemed destined to find the net. Once again, Courtois managed to get a fingertip to it, turning it onto the base of the post.
Milan, already without the suspended Sulley Muntari and Riccardo Montolivo, lost Mattia De Sciglio to injury, but still Atlético struggled to rediscover their initial tempo. Kaká, who shook off an ankle problem to start, went close again after collecting a Mario Balotelli's back-heel – for once, Courtois was beaten, yet the shot flew just over. Moments before the interval Balotelli tried his luck, sending a powerful strike from distance whistling past Courtois' left upright.
Diego Costa missed the target with an acrobatic bicycle kick early in the second half, Kaká failing to trouble the keeper too with a low effort from the edge of the area. Cutting in from the right, Taarabt also had a glimpse at goal though his low attempt was blocked by an Atlético defender as Milan raised the pace after a slow opening to the half.
The Spanish visitors soaked it all up and, into the final stages, began probing forward themselves. It brought immediate reward as Diego Costa headed in from close range after substitute Ignazio Abate was unable to clear Gabi's corner from the right. It gives Atlético a narrow lead to take into the return on 11 March but all is not lost for Milan – Seedorf, of course, knows all about that.