Former Chelsea manager Jose Mourinho says that ex-England midfielder Frank Lampard was the top player he saw in the Premier League for a decade.

On a visit to Singapore, Mourinho stopped short of naming Chelsea's all-time leading goal-scorer as the best he'd ever managed but said he stood out.

"At Chelsea, in my first period, I had Frank Lampard, probably the best player in the Premier League for one decade," Mourinho told the Straits Times.

"Who was my best player? It's so difficult to say and I coached some of the best players in the world."

Mourinho, who visited Singapore's Northlight School on the invitation of the Singapore Olympic Foundation on Wednesday, added that there were other international stars at the top of his list.

"I went to Inter [Milan], I had [Zlatan] Ibrahimovic, I got [Javier] Zanetti. I got to Madrid, I had [Cristiano] Ronaldo. I come back to Chelsea and I find other top players," he said.

"If have so many, they gave me so much, it's not fair to say this is the one. It's impossible to win so many things without the players so I respect all of them."

Mourinho, who won UEFA Champions League titles at Porto and Inter, rates his defeats in the elite European competition as his biggest disappointments.

"I was lucky to be in the finals, but I also lost in the semifinals on penalties," he said. "I lost at Chelsea-Liverpool on penalties, I lost at Real Madrid-Bayern Munich on penalties too.

"When you lose the semifinals on penalties, you get the feeling that you did everything right and you are not lucky. I have these moments but I cannot complain because when you win twice, you have to accept that it's part (of the game) to lose two semifinals."

Frank Lampard was one of Jose Mourinho's trusted generals at Chelsea. Shaun Botterill/Getty Images

Arsenal, Manchester United and Barcelona were among the clubs he enjoyed beating the most, Mourinho revealed during his Singapore trip.

"At Chelsea the first time, it was a period when Arsenal was a big rival and Manchester United, of course," he said.

"Then I go to Milan, there are big derbies, so Inter vs. Milan, Inter vs. Juventus. I go to Madrid, of course Barcelona was a rival. I come back to Chelsea now it was not about Man United and Arsenal. Manchester City was coming very strong in the last few years."

During his Singapore visit, the 53-year-old played down speculation that he would take over at Manchester United, saying only "it's a million dollar question that nobody knows" and that "starting the next season with a new club and project is probably the best thing for me."

Mourinho was with football agent Jorge Mendes, plus Singapore billionaire and Valencia club owner Peter Lim.

The contract of Singapore head coach Bernd Stange is due to expire later this year, prompting Mourinho to joke that he was rumoured to be linked with the role.