The Latest on the U.S. Open (all times local):
Simona Halep gave herself "less than 9" for her quick work in Kirsten Flipkens 6-0, 6-2 in the first match on Arthur Ashe Stadium.
The Romanian was ahead 6-0, 5-0 with countrywoman Nadia Comaneci cheering her on. Comaneci was the first gymnast to score a perfect 10 at the 1976 Montreal Olympics.
Halep says she wasn't perfect, but pleased with how she played against the Belgian. She got 69 percent of her first serves in and won 12 of 15 points at the net.
Halep, who reached the semifinals of the U.S. Open last year, will next face Lucie Safarova, a 6-4, 6-4 winner over Daria Gavrilova.
Venus and Serena Williams are among the featured matches on Arthur Ashe Stadium at the U.S. Open.
Venus will take on Kateryna Kozlova of Ukraine in the afternoon Tuesday before her top-ranked sister plays Ekaterina Makarova of Russia in the night match at the stadium with the new retractable roof.
Serena has been bothered by a shoulder injury, playing only three matches since winning Wimbledon for her 22nd Grand Slam title. She faces a tough opening opponent in Makarova, who beat her at the 2012 Australian Open.
Kirsten Flipkens of Belgium and Simona Halep of Romania have started play on Ashe, followed by Fernando Verdasco of Spain against Stan Wawrinka of Switzerland.
Andy Murray of Britain will face Lukas Rosol of the Czech Republic in the other evening match.