Roger Federer [ Images ], revelling in the unusual role of being the underdog, will continue his bid for a fifth successive US Open [ Images ] title on Friday when he plays little-known Brazilian Thiago Alves in the second round.

The Swiss, relegated to second seed in New York after losing his number one ranking to Spaniard Rafael Nadal [ Images ], is trying to avoid ending the year without a Grand Slam title for the first time since 2002.

Having lost to Nadal in both the French Open [ Images ] and Wimbledon [ Images ] finals, Federer is a rare underdog, something the crowd appears to be responding to.

"The change I feel is fans are really supporting me and telling me I'm still number one and the best -- 'you're going to be there again' and stuff," Federer said.

"So I feel like I've got unbelievable support from the fans watching me and seeing people in the streets and stuff. It's really nice."

Third seed Novak Djokovic [ Images ], runner-up to Federer last year, faces American Robbie Kendrick in the second round.

Former champions Andy Roddick [ Images ] and Marat Safin [ Images ] are also in action. Eighth seed Roddick takes on Latvian teenager Ernests Gulbis [ Images ], while Russian Safin plays 15th seed Tommy Robredo [ Images ] of Spain.

In the women's event, second seed Jelena Jankovic [ Images ], one of five players who could be ranked number one at the end of the tournament, plays China's Zheng Jie [ Images ] in a third-round match.

Olympic [ Images ] champion Elena Dementieva [ Images ] and former champion Lindsay Davenport [ Images ] are also in third-round action.