Thomas Tuchel described being appointed Chelsea manager as "the best present still left under the tree" after being sacked by Paris Saint-Germain over Christmas.
The German won two Ligue 1 titles in his two full seasons in the French capital and led the club to their first-ever Champions League final.
But he was dismissed last month after an inconsistent start to the season and clashes with sporting director Leonardo.
Chelsea sacked club great Frank Lampard on Monday after a run of five defeats in eight Premier League games, with the London club facing a battle just to qualify for the Champions League next season.
Tuchel's first match in charge ended in an underwhelming 0-0 draw at home to Wolves on Wednesday.
But he believes a richly talented squad bolstered by £220 million ($300 million) worth of new signings in the summer transfer window can still win silverware this season.
"I had a pretty rubbish Christmas job-wise and suddenly four weeks later I find the best present still left under the tree," said Tuchel at his unveiling on Thursday.
Chelsea face Barnsley in the FA Cup fifth round and Atletico Madrid in the Champions League last-16 next month.
Tuchel is targeting both competitions and wants Chelsea to mount a challenge for the Premier League title next season.
"We have to be ready to compete for trophies, there is no time to waste," he said.
"We compete now for the FA Cup, we are ready to compete at the highest level in the Champions League.
"We want to create a team that is absolutely no fun to play against. Next season we want to be ready to close the gap to Man City, Liverpool and the others."
One of Chelsea's big summer signings, Timo Werner, has failed to produce the prolific form he showed in the Bundesliga for RB Leipzig.
Werner has scored just once, against fourth-tier Morecambe, in his past 17 games for club and country and was left on the bench for the full 90 minutes by Tuchel against Wolves.
Restoring the German international's confidence will be one of the new manager's major challenges at Stamford Bridge and Tuchel said he can sense Werner's lack of belief.
"In the moment I see the weight is on his shoulders," said Tuchel. "He cares a lot. That shows he is a fantastic character.
"Sometimes as a striker it is better not to care at all, but he's not that guy.
"He cares and he's not happy with himself and with the way things went lately. Right now it's important to rebuild his trust, re-find a smile on his face and stop doubting too much."