He said: "We know the importance of the away goal in European cups, that is why I was very pleased to help the team to win this game.

"We managed well the game and we were confident, but we faced obviously a great team and we were very, very committed.

"We knew their main strengths and I think we dealt with that. Now we just need to stay focused and finish the job at home."

Chelsea's 11-goal hitman praised the attention to detail of manager Thomas Tuchel, who has won six of his eight games since his arrival on January 26.

The 47-year-old took his former club Paris St Germain to the Champions League final in August and has made a great start to life in London.

"We came here with strong intentions to win the game and play our game," Giroud told BT Sport.

"We analysed well their game and knew how we could give them trouble offensively and I think we have been very strong at the back all together with defensive shape.

"We are very pleased with the win, we had the better chances and I think it is a deserved win."

Ex-Arsenal forward Giroud was forced to wait before he could celebrate finding the net in the 68th minute.

Initially the strike was ruled out for offside, with Mason Mount adjudged to have knocked the ball forward, but VAR awarded the goal after Atletico defender Mario Hermoso was deemed to have diverted the ball into the path of the Chelsea ace.

"Obviously I didn't know what to think about the goal because I just tried to focus on hitting well the ball," Giroud explained.

"I love overhead kicks and I was pleased to see the ball hit the back of the net.

"To be honest I had no clue about being offside or not, Mas told me he didn't touch the ball so it came from the defender, but apparently I was not off. It is good for the team and good for me."

Atletico's narrow defeat made it two losses in a row for the LaLiga leaders and only one win in five games in all competitions.

While Diego Simeone's team are without numerous players, notably England full-back Kieran Trippier through suspension, they struggled to create chances in Romania and failed to have a single shot on target.

The Argentinian conceded work is to be done ahead of the second leg in London next month.

"It's a little difficult period but we have to improve ourselves. OK, they are 1-0, but we just have to go and hope we can turn it around," Simeone said.

"There are still three weeks to think about that game but for sure the second leg we have to think better for things to do against Chelsea."