Italy\'s Sara Errani and Roberta Vinci won the US Open women\'s doubles title on Sunday with a 6-4, 6-2 triumph over Czech third seeds Andrea Hlavackova and Lucie Hradecka. It marks the second Grand Slam title of the season for the Italian duo, best friends who also claimed the French Open, and the eighth doubles title of the year for the second seeds. \"We played unbelievable here,\" said Vinci. \"We are so happy.\" Errani will become the World No. 1 in women\'s doubles on Monday with Vinci ranked second. \"We will be No. 1, not only me,\" Errani said. \"We are playing very good. We\'re friends. We enjoy playing. It\'s great.\" The Czech duo fell in 76 minutes. \"They are No. 1 in the world. What can you do?\" Hlavackova said. \"Hopefully another day we\'re going to beat them.\"