The 29-year-old Spaniard beat Japan's Kei Nishikori 6-4 7-5 in the final of the Barcelona Open on Sunday to extend his clay-season winning streak to 10 matches for 2016.
Nishikori, a Barcelona winner in 2014 and 2015, paid a steep price for missing out on a flurry of break point chances throughout the match. Nadal saved seven of the eight breakpoints the Japanese held against him in the first set.
Argentine Vilas won 49 clay-court titles in the 1970s and early 1980s.
Nadal can go one better in May as he is slated to play at Madrid and Rome, as well as at the French Open, where he will be gunning for a record 10th Roland Garros crown.
"I think I served well which was very important," said the world number five. "The fact I had a good percentage of first serves allowed me to play better. In the second set I let a lot of opportunities go, but I am very happy to have resisted mentally and happy to win," Nadal said.
Last Updated 31, Mar 2018, 6:49 PM IST