Atletico Madrid coach Diego Simeone has rued his side's lack of killer instinct following the 2-1 Champions League defeat by Benfica at the Vicente Calderon.
Angel Correa fired the hosts into a first-half lead but missed opportunities from Jackson Martinez, either side of the opener, proved costly for the Rojiblancos.
Nicolas Gaitan levelled up on 36 minutes, before Goncalo Guedes added another early in the second half as Atleti ultimately slumped to their first home defeat in the competition since March, 2014.
"It was a great game and our opponents did very well in defence," Simeone told reporters. "We had chances to stretch our lead in the first half, but it wasn't to be.
"We need to focus on our finishing. It's obviously a bad result, but we always had the right attitude.
"We are second in the group so we're relaxed and we have to wait for the next round of games to see how the group pans out."
Madrid sit second in Group C, two points clear of Galatasaray and Astana, three behind the Portuguese side.
Shane Callaghan
