Preliminary Nielsen ratings give NBC's "Late Night with Jimmy Fallon" a decisive, if predictable, win in its debut.

Fallon beat CBS' "Late Late Show with Craig Ferguson" by a 35 percent margin in their first head-to-head clash Monday.

The inevitable curiosity about Fallon's first night helped the show post a one-third boost over the average ratings performance by Monday airings of "Late Night" so far this season.

Taking over as host from Conan O'Brien, Fallon had Robert De Niro, Justin Timberlake and Van Morrison as guests on his first show.

These early Nielsen numbers measure viewership in 56 of the top U.S. markets, which reflects about 70 percent of the nation's total 114.5 million TV homes.

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