The Frenchman, who won the World Cup with his country over the summer, has played 200 times in the Premier League for Arsenal and Chelsea.
He spoke to the club's official website about how Maurizio Sarri has invigorated the club.
"We have a great challenge this year, we have a new coach with new ideas," Giroud said.
"We’ve started a new chapter at the club, the coach is trying to teach us his philosophy of the game which we’ve understood well and it’s been a good start to the championship.
"We can still improve, there is always room for improvement but we are on a good run and even if we should have won the game against Liverpool, we are in form.
"We are working a lot on tactics, on the pitch and off the pitch with videos.
"We work through video sessions and with a lot of tactics on the pitch.
"We are doing well, we have a nice understanding with each other and we know exactly what we have to do."