Jimmy's joy at being Blue
Blues boss Claudio Ranieri has a glut of attacking options at his disposal, following the financial injection provided by new owner Roman Abramovich, but Dutch ace Hasselbaink has fought off the challenges to keep his place in the team.
Hasselbaink is also driven by the desire to represent his country at next summer's European Championships.
"I knew that this year was going to be important for me because I want to go to the European Championships," he told Chelsea TV.
"Last year was a really difficult year for me. I was injured quite a lot. I came back from a really nasty injury and then I had a really good pre-season.
"I think I'm the kind of player who needs to be fit to be playing really well and I need my pre-season.
"This year, I had a really good pre-season. I was training every day and every day hard.
"Even in my holidays, I was training for myself and I think I have benefited from that point.
"If my football is better from that, I don't know, but I definitely feel better inside and that helps. I feel stronger, I feel I can do more and it helps."
Hasselbaink feels Chelsea have a real chance of winning The Premiership this season, and is happy to still be a Stamford Bridge player.
He added: "I did not want to go, I wanted to stay and I wanted to fight for my place.
"At the beginning of the season, I didn't know that many players were going to come but at that moment I already knew I wanted to stay and play football and enjoy myself again.
"Now that there's been a lot of signings, it makes it a little more exciting for me because we can play for the championship, we can play for the FA Cup and definitely do well in the Champions League, because we have got a great squad."