In a tie played in Romania instead of Spain because of Covid-19 restrictions; Giroud demonstrated athleticism and technique to send an acrobatic effort beyond Atletico keeper Jan Oblak in the 68th minute.
The goal was originally ruled out for offside before a video assistant referee review revealed the ball had bounced off Atletico defender Mario Hermoso.
Chelsea has now gone eight matches unbeaten; since Tuchel succeeded Frank Lampard while Giroud is emerging as their Champions League talisman after scoring all four goals in the group-phase victory against Sevilla and a last-minute winner away to Rennes.
Chelsea was regarded as underdogs in this last-16 tie against the La Liga leaders but apart from a couple of early scares; keeper Edouard Mendy’s carelessness early in the game before Suarez flashed the ball across the face of goal; they were in charge.
It was also a good night for young England forward Callum Hudson-Odoi; who performed creditably after the debate surrounding his substitution; after coming on as a substitute in Saturday’s 1-1 draw at Southampton.
Hudson-Odoi was replaced again after 79 minutes in Bucharest but this was after a performance full of energy and hard work that will have delighted taskmaster Tuchel on a highly satisfying night for Chelsea.
Atletico adopted a more conservative approach than Chelsea despite this being their ‘home’ leg, albeit on the neutral territory; and Suarez was reduced to familiar moments of gamesmanship in a bid to unsettle his opponents. It was all to no avail as the Premier League side held firm.
It was a game; that pointed to Chelsea building the platform for progress in the second leg; but Atletico’s resilience, ability to fight the odds, and love of being the underdog still makes them a threat.