NOTTINGHAM, England (Reuters) -Chelsea boss Enzo Maresca had strong words for his team's doubters after they secured their first Champions League berth in three seasons on Sunday, with the youngest team in Premier League history.

Levi Colwill struck in the second half in Chelsea's 1-0 victory at Nottingham Forest in a make-or-break final game of the campaign that saw Maresca's team finish fourth, and left Forest in seventh with a Conference League berth next season.

The average age of Chelsea's starting eleven this season was 24 years and 36 days -- the youngest ever by a team in a single Premier League campaign, according to Opta Sports.

"I didn't have any doubt about the players," Maresca said. "I said that the doubt was from outside, all the ones (who think) that they have the answer, or all the ones that they have the truth, they were saying that we are too young. We are not good enough.

"They were saying that we were not able to win on this pitch because we're too young, because we're not experienced. And unfortunately for them, they have all been wrong."

Chelsea, who started the day in a five-team battle for the three remaining Champions League positions, return to Europe's top club competition for the first time since 2022-23.

Team owner and chairman Todd Boehly embraced Maresca on the City Ground pitch after the final whistle.

"So many people before the season, during the season had disbelief. They told us we were too young, inexperienced and were not going to make it," Chelsea captain Reece James said. "But here we are."

Maresca said his first season with the club was a success because everyone was on the same page.

"With the club, with the owners, with the sport director, the players, we all go in the same direction," the Italian said. "And I said many times during the season that the (negative) noise was more from outside than from inside."

Forest's defeat was a disappointing ending to an otherwise remarkable season. They were tipped for a potential relegation battle when the campaign kicked off, but parked themselves in the top five for much of the season.

"We are disappointed, but it's a couple of hours then when you're going to look back and realise that it's been good," Forest boss Nuno Espirito Santo said.

"It's tough to take, we knew that the last game was going to be very difficult for all the (five) teams involved in this fight, and we came up short.

"There was a point when we knew that one goal could change everything, and this is what the perception does to you -- what if?"

(Reporting by Lori EwingEditing by Toby Davis)