French frontman Giroud scored the only goal of the game in the 70th minute with a fantastic overhead kick. The strike was initially ruled out for offside, but was eventually given when the VAR showed that the ball had fallen to the Chelsea forward after a touch from Atletico defender Mario Hermoso.
German striker Timo Werner had a good chance to double the lead in the closing stages of the game, but fired his effort wide. In another Round-of-16 clash, defending champion Bayern Munich thrashed Italian outfit Lazio 4-1 in Rome.
Robert Lewandowski, Jamal Musiala and Leroy Sane netted a goal each for Bayern while Francesco Acerbi helped the German side with an own goal. Joaquin Correa scored a consolation goal for Lazio four minutes into the second period.