Simeone's Atletico triumph in Milan
Diego Costa headed a late goal to give Atletico Madrid a 1-0 win at AC Milan in their Champions League last-16 first-leg game after the hosts were twice denied by the woodwork in the first half.
Costa scored at the far post after the Milan defence failed to clear a corner as the side coached by Diego Simeone won a fast, furious and often scrappy and bad-tempered match.
Milan had created the better chances and were frustrated as Kaka had a delightful curling shot tipped on to the crossbar by Atletico goalkeeper Thibaut Courtois who also deflected Andrea Poli's header on to the post in a dramatic first-half spell.
Clarence Seedorf, who won the Champions League four times as a player with three different clubs, made his coaching debut in the competition in charge of Milan.
In today's other match, both teams missed penalties, Arsenal had goalkeeper Wojciech Szczesny sent off and Bayern Munich won an incident-packed Champions League last-16 first leg 2-0 at the Emirates Stadium.
The holders opened the scoring with a brilliantly executed right-foot curler from Toni Kroos after 54 minutes that gave substitute keeper Lukasz Fabianski no chance.
Arsenal had earlier spurned an opportunity to go ahead when Mesut Ozil's weak penalty was easily saved by Manuel Neuer in the eighth minute.
The home team were then reduced to 10 men when Szczesny was sent off for clattering Arjen Robben after 38 minutes but David Alaba fired his penalty against the foot of the post.
Midfielder Santi Cazorla was taken off when the Arsenal keeper was dismissed but Fabianski had no chance when Thomas Mueller added the second goal in the 88th minute.