All three of the opponents whom Hikaru defeated were rated around 2150. His opponents were Jerry Mc Clinton rated 2144, William W P Perez rated 2131 and Joel P Chu rated 2192.
Hikaru Nakamura became the youngest rated chess master in US history in a tournament at the Marshall Chess Club on February 26. Because the February 1 rating list was used to determine entries into the New York Open, he was allowed to play in the Under-2200 section using his old rating of 2044.
Hikaru Nakamura is 10 years, 3 months old. He has only been playing chess for 11 years.
You can now look up the official ratings of Hikaru Nakamura at the US Chess Federation web site.
Here are links: