The 31-year-old France worldwide joined Chelsea from London rivals Arsenal in an £18m deadline day move this January, as part of a triangle of moves that saw the Gunners sign Pierre-Emerick Aubameyang and Dortmund take the Blues' Michy Batshuayi on loan.
The Chelsea striker had been struggling with a niggling back injury since mid-January before returning for a 30-minute cameo in Monday's 3-0 win over West Brom.
Defending champions Chelsea have seen their Premier League crown slip, with Manchester City dominating the battle for domestic supremacy in 2017-18. "He is an important player - we have a lot - but when he is on tune, he is very hard to play against", he added.
"We have big games against other teams in the bottom half of the table - they're really big six-pointers".
"I had five awesome years [at Arsenal], but now it's a new chapter of my career and I am focused 100 percent on the Blues to reach our targets". I was very happy to set up the goal for Eden. I know I will have to be efficient, assist sometimes, score sometimes.
Giroud said: "It's been a while since I played regularly and that's why I needed to move".
'Obviously I had the studs on my head, and afterwards I needed some stitches at half-time, but I feel okay.
He pointed out that many players have been tempted away from the Premier League to La Liga in recent times. It's a massive club and I am very proud to be here and to carry on my career.
"We have 11 games to play between now and then and we have to give everything to achieve that".
Chelsea climb into fourth with the gap between Manchester United in second and fifth-placed Tottenham Hotspur now just four points in the race to join runway leaders Manchester City in next season's Champions League.