Serena stays on course

Serena Williams made sure of her place in the third round of the US Open with a routine 6-2 6-4 victory over Maria Jose Martinez-Sanchez.

The Olympic champion was not on her best form but did enough to see off the challenge of the Spanish left-hander in 82 minutes.

The players had met three times before with Williams winning all of their previous encounters.

The fourth seeded Williams smashed six aces and won 89 per cent of points on her first serve, but Martinez-Sanchez put up more of a fight in the second set.

The Spaniard, ranked 108th in the world, even managed to break her American opponent but Williams responded with two breaks of her own to seal the win and set up a meeting with Russia's Ekaterina Makarova.

Crisis

Crowd favourite Ana Ivanovic also eased into the third round with a comfortable win over Sofia Arvidsson on Arthur Ashe Stadium.

The Serb was tipped for glory after winning her first Grand Slam title at the French Open in 2008 and becoming world number one, but instead injuries and a crisis of confidence hit and she has never really recovered.

Remarkably, since her Roland Garros triumph, she has not been past the fourth round at any Grand Slam and has gone out in the first round of all of them over the past three years.

This year has also been patchy. The 24-year-old won only one game against Victoria Azarenka in the fourth round of Wimbledon and, hampered by a foot problem, she was thrashed 6-0 6-0 by Roberta Vinci in her last match before the US Open.

But it has been so far, so good at Flushing Meadows and she hit 39 winners in a 6-2 6-2 victory over Arvidsson on Thursday.

The first-round loss for eighth seed Caroline Wozniacki has opened up Ivanovic's draw and a quarter-final appearance looks well within her grasp.

Radwanska scare

Fellow Serb Jelena Jankovic, whose career has also been on a downward spiral, progressed with a 6-4 6-2 win over Lara Arruabarrena-Vecino, while there were also wins for Dominika Cibulkova and Maria Kirilenko.

Russia Kirilenko, the 14th seed, has been in fine form this summer and she beat Hungary's Greta Arn 6-3 6-2, while 13th seed Cibulkova had a tougher time in a 7-6 (7-3) 7-6 (7/3) victory over Bojana Jovanovski.

Second seed Agnieszka Radwanska survived a major scare before booking her place in the third round of the US Open.

The Pole was a set and a break down to the experienced Spaniard Carla Suarez Navarro but incredibly won the next 11 games to advance 4-6 6-3 6-0.