The former top ranked women's player need only 43 minutes to dispatch of Denmark's Eva Dyrberg, 6-2, 6-1, in first round action in Flushing, New York.
The U.S. Open is Davenport's first Grand Slam event of the year.
She returned to action last month after missing a majority of the 2002 season while recovering from knee surgery.
Lindsay Davenport acknowledges cheers following Monday's match. (AP Photo)
Davenport arrived at the Open with an 11-3 match record for the season after missing the Australian and French Opens and Wimbledon because of her surgery.
The 1998 champion and the 2000 U.S.Open runner-up, Davenport has been to the final of the last two events she's participated in.
"I don't know if it will take beating a Williams or a very top player to get me going or if it takes winning some more tournaments, but I'm not there," Davenport said.
Last Saturday, she lost to Venus Williams in the final of the Pilot Pen Tennis event.
A week earlier, Davenport fell to Chanda Rubin in the JPMorgan Chase Open championship.
Corina Morariu returned to the Grand Slam spotlight, too, less than 11/2 years after starting treatment for leukemia, but fell to fellow American Serena Williams, the No. 1 women's seed, 6-2, 6-3.
"I didn't think that I'd ever be back here," Morariu said. "There are days when you feel so bad and things get so difficult that you don't think you'll be able to do the things you used to."
"There were definitely a lot of emotions. When you have a tough time walking up the stairs in your house, it's tough to imagine that you'll be able to play with Serena Williams."
"It takes a lot of courage and character to do what she's done," Williams added.
With wins already this year at the French Open and Wimbledon, Serena is attempting to become the first woman since Steffi Graf did it in 1996 to win three consecutive Grand Slam titles in one season.
Venus and Serena, the top two seeds, could meet only in the final, which they have done in two straight and three of the last four majors.
In other wonen's action, eighth-seeded Justine Henin easily beat American Samantha Reeves, 6-1, 6-2, while Elena Dementieva defeated Saori Obata 6-2, 6-4.
Fifth-seeded Jelena Dokic of Yugoslavia also advanced, but Anna Kournikova of Russia registered 40 unforced errors in a 6-3, 6-0 loss to Angelique Widjaja of Indonesia.
1994 Open champion Arantxa Sanchez Vicario of Spain, the 25th seed, was beaten 6-3, 6-1 by Marion Bartoli of France.
Andre Agassi, the 1994 and '99 U.S. Open winner, beat compatriot Robby Ginepri 6-3, 6-3, 6-3 in an emotional evening at the USTA National Tennis Center.
First, the American flag recovered from the World Trade Center and raised by the U.S. Marines in Afghanistan was flown at the Open.
Then, Billie Jean King and John McEnroe, two of tennis' most popular and engaging champions, led a procession of flags on-court during a special opening-night ceremony.
Honour guards from the New York Police Department, New York Fire Department, Port Authority Police Department and the U.S. Marine Corps participated in the ceremony, as did the New York Police Academy cadets, carrying the U.S. colours.
"This year's Open is special," New York Mayor Michael Bloomberg said. "It's another indication that our city is well on its way to recovering from the tragedy of September 11."
Even though Agassi is the sixth seed, he enters this event as a strong favorite to win the U.S. Open for a third time.
He was the runner-up in 1990 and '95 and tops all active players with 40 hardcourt titles, including one in Los Angeles last month.
Other winners included two-time major champion Yevgeny Kafelnikov of Russia, French Open winner Albert Costa of Spain, No. 13 Roger Federer of Switzerland, No. 25 James Blake of the U.S., and American veteran Michael Chang.
Men's top seed Lleyton Hewitt, who won last year's tournament over four-time Open winner Pete Sampras, enters the tournament attempting to become only the seventh man in the Open Era to win back-to-back U.S. Open titles.
Hewitt will play his opening-round match Tuesday or Wednesday.
No Canadians qualified for singles play at the tournament.
with files from Sports Network
