Xabi Alonso said Chelsea's ambition was "very clear" after Clearlake Capital took full control of the Premier League club, ending Todd Boehly's chairmanship.
Chelsea announced late on Wednesday that Clearlake, led by co-founders Behdad Eghbali and Jose E. Feliciano, would acquire the stakes of Boehly and director Mark Walter.
US billionaires Boehly and Walter partnered with Clearlake to buy the club from Roman Abramovich in May 2022 in a sale mandated by the British government.
Before the new deal, private equity company Clearlake had owned 61.5 per cent of the club, with Boehly and Walter carving up the remaining shares with another investor, Swiss billionaire Hansjorg Wyss.
Chelsea said Wyss would "remain an important stakeholder and partner in the ownership group".
Boehly and Walter are among the co-owners of the Los Angeles Dodgers baseball team, while Walter recently sold the Los Angeles Lakers basketball franchise for $12.5 billion.
The Financial Times reported that the pair were set to receive £950 million ($1.27 billion) for their combined stakes in Chelsea, in a deal that values the club at about £5 billion including debt.
In a fresh statement on Thursday, Chelsea said: "Our ambition is clear: to compete at the highest level, to win major trophies, and to build sustained success."
Blues boss Alonso, who started his role at Chelsea on 1 July, told reporters that the change was "an important day for the club".
"Thanks to the former owners for what they've done. I was not here, but I know they played an important role," he said on the eve of Chelsea's Premier League match at Brentford on Friday.
"And now that Behdad is taking more control, almost full control, I think it's good that the main one is clear.
"I have very good relations with Behdad. He was the one that came to Madrid to explain me the project, to convince me, and we are working well together."
The Spaniard added: "We know where we want to be, we know that everything takes time, but the ambition for that is very clear."
MIXED START TO NEW CAMPAIGN
Since the takeover in 2022, Chelsea's highest Premier League finish was fourth, in 2024-25, while the club won the Uefa Conference League and Fifa Club World Cup that season.
Former Real Madrid and Bayer Leverkusen coach Alonso has a brief to revitalise an underachieving Chelsea squad that finished a dismal 10th in the Premier League last season.
The Blues have made a mixed start to the new campaign, taking seven points from their four Premier League games to sit sixth in the table.
Boehly and Walter have also sold their stakes in Chelsea's partner club, French Ligue 1 side Strasbourg, giving full control to Clearlake.