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 Spaniard in 82 minutes. The players had met three times before with Williams winning all of their previous encounters. And Thursday's match soon looked to be going the same way on Arthur Ashe Stadium as Williams broke twice in the opening set while saving four break points. The fourth seed also smashed six aces and won 89% 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. | 
