Diego Costa's late strike has given Atletico Madrid a 1-0 victory over AC Milan in the San Siro in the first leg of their Champions League last-16 tie.

Milan had the best of the early opportunities, with Thibaut Courtois being called upon to push Kaka's powerful effort against the crossbar.

Atletico's Belgian goalkeeper was forced into action once again to deny Andrea Poli, who looked certain to score with a header from close range.

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Milan tested the frame of the goal once again in the 32nd minute and it was Kaka who was left frustrated when he fired against the crossbar from inside the box.

The visitors came close to taking the lead late in the first half but Ignazio Abate managed to remain calm to clear the danger under heavy pressure from Costa.

Clear opportunities proved to be difficult to come by in the second half as both sides wrestled for superiority in a tight contest.

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Kaka looked to be the most likely to make the breakthrough but the Brazilian continued to be frustrated, picking out Courtois with an effort from the edge of the box.

Raul Garcia came close on a couple of occasions late in the match but he drilled his first effort wide from a tight angle before miscuing a shot over the crossbar in the closing stages following good work from Juanfran.

However, there was still time left on the clock for Atletico to score a crucial away goal in the 83rd minute thanks to Costa, who jumped highest to powerfully head home from a corner.