LONDON (AFP) - Chelsea manager Jose Mourinho said his side had won the toughest league in world football after a 1-0 victory over Crystal Palace on Sunday saw them crowned English champions.

Eden Hazard's goal on the stroke of half-time gave the Blues a 1-0 win in front of their own fans at Stamford Bridge and an unassailable 16-point lead at the top of the Premier League table.

Chelsea have now won the title three times under Mourinho but this is the first since the Portuguese manager returned to the London club for a second spell in charge in 2013.

Mourinho, whose trophy-laden career also includes domestic titles in Portugal, Italy and Spain, told Sky Sports: "When I came back I knew that I was coming back to the most difficult league to win in the world of football. And we've done it.

"Crystal Palace were fantastic with the way they have played. They were like they need the game to be champions or to not be relegated. For a team that is middle of the table that is fantastic and is the nature of football here," he added.

"From day one to today nobody gave us anything. Everything we got we deserved."

And Mourinho said the very strength of the Premier League, may work against Chelsea's bid to add a second European Champions League crown to the one they won under Roberto di Matteo in 2012.

"The group starts with the League Cup and the Premier League but we know in future it's very difficult and other teams will come even stronger," Mourinho said.

"England's not the best country to be a force and dominate football."

In a separate interview with the BBC, the 52-year-old Mourinho said: "I am very happy and proud. I need a rest, I'm tired. It's not easy to cope with that, but finally mathematically we are champions now. Finally we can breathe, relax and enjoy.

"I think last season we were building something. I always thought when this season started, and then winning match after match, I was feeling the team would be ready," Mourinho said.

"I knew the work ethic would be there and the spirit would be there. The mentality in key moments in the season was there," he explained after Chelsea took the title with three games to spare.

"I thought we had everything to win the title," added Mourinho who also masterminded back-to-back Blues triumphs in 2004-05 and 2005-06.

Asked to rank this latest success alongside his other triumphs, Mourinho said: "I don't compare with the past, no. I can say it's very difficult, because the Premier League is changing and everything gets stronger.

"The English game is still my favourite. I could be smarter and like other mangers choose teams and countries where it's easy to be champions, where they can enjoy calmly their success," added Mourinho, who returned to Chelsea from Spanish giants Real Madrid.

"I chose a country where it's difficult to win and a club without a big tradition of winning Premier League titles because the last one was in 2010. I chose a difficult job."

Sunday's win also set the seal on a difficult few days for Mourinho, who flew back to Portugal after Chelsea's 3-1 win at Leicester on Wednesday because his 76-year-old father was seriously ill and had to undergo surgery to his head.

But Mourinho said his father, also called Jose and himself a former professional goalkeeper and manager, was making a good recovery following the operation.

"When the game finished at Leicester, I immediately got a private plane to go to Portugal and I was there with him in the most difficult moment, which was the moment of surgery," Mourinho said.

"Apart from that, everything is under control. He's strong and is getting better and better and better and better and better. So I'm much more relaxed."