Qualifier Ashutosh Singh of Delhi and wild card Ankita Raina of Gujarat carved out contrasting victories to clinch the men's and women's national titles respectively at the Vishwarupa Tubes National Grasscourt Tennis Championship here Saturday. Ashutosh pipped P C Vignesh of Andhra Pradesh 0-6, 7-6(3), 6-2, Ankita shut out Karnataka girl Sheethal Goutham 7-6 (2), 6-2 at the Calcutta South Club