In Conversations with Stalin by Yugoslavian Communist Milovan Djilas the author talks about his meetings with Stalin and other Soviet top brass. The following extract from a meeting on February the 10th, 1948 interested me particularly (emphasis mine):

Stalin then turned to the uprising in Greece: 'The uprising in Greece has to fold up.' (He used for this the word svernut', which means literally to roll up.) 'Do you believe'- he turned to Kardelj- 'in the success of the uprising in Greece?' Kardelj replied, 'If foreign intervention does not grow and if serious political and military errors are not made.' Stalin went on, without paying attention to Kardelj's opinion: 'If, if! No, they have no prospect of success at all. What do you think, that Great Britain and the United States- the United States, the most powerful state in the world- will permit you to break their line of communication in the Mediterranean Sea! Nonsense. And we have no navy. The uprising in Greece must be stopped, and as quickly as possible.' Someone mentioned the recent success of the Chinese Communists. But Stalin remained adamant. 'Yes, the Chinese comrades have succeeded, but in Greece there is an entirely different situation. The United States is directly engaged there- the strongest state in the world. China is a different case, relations in the Far East are different.

So when was the first recorded time that Stalin considered the US a great power, and was this the first time the US was considered a greater power than the Soviet Union? I was surprised at Stalin's admission in the extract. Frankly I expected him to be too prideful to admit that, even in a private meeting with other Communists. Are there any public statements by Stalin where he describes the US as more powerful than the Soviet Union?

Thanks.