Czech Petra Kvitova has strengthened her position in the top five of the WTA world rankings following her triumph in the New Haven Open at the weekend, as Victoria Azarenka of Belarus remains in top spot. Kvitova won the New Haven title thanks to a 7-6 (11/9), 7-5 final victory against Maria Kirilenko of Russia, who climbs two places to 12. Italy's Roberta Vinci has broken into the top 20 after beating Jelena Jankovic in the final of the Texas Open in Dallas last week.