US Open Nadal Rafael 2010
Showing more power than ever in his serve and looking comfortable on the fast Arthur Ashe center court, the 24-year-old Spaniard claimed the first two tiebreaks by 7-4.
Top seed Nadal, who topped 130 mph (210 kph) on his fastest serve, registered the first service break of the match when the 93rd-ranked Gabashvili netted an easy forehand in the seventh game.
Nadal then closed out the match with another break.
"My serve tonight worked well," said the eight-times Grand Slam winner, who needs a US Open title to complete a career grand slam. "Hopefully it will continue like this.
"My serve is not my best shot but I always try hard to keep improving and that's what I'm working on all the time."
Nadal, decked out in black with electric green shoes and accents on his shirt, served up seven aces and pounded in 67 per cent of his first serves in a match that lasted nearly three hours.
"I know if I want to have chances to win here ... I need to serve really, really well, so that's one of the things I am most focused on," said Nadal, winner of five French Opens, two Wimbledons and one Australian Open.
Nadal, winner of this year's French and Wimbledon championships, will next meet Denis Istomin of Uzbekistan, a straight sets 7-5 7-5 6-1 winner over Maximo Gonzalez of Argentina.
Top-seeded Caroline Wozniacki of Denmark made short work of American wildcard Chelsey Gullickson, breezing into the second round with a 6-1 6-1 victory to close out Tuesday's programme.
Wozniacki, who has compiled a 14-1 record since Wimbledon and won four titles this season, had a light workout against Gullickson, a University of Georgia All-American playing in her first Grand Slam.
The 20-year-old Dane, runner-up to Belgian Kim Clijsters at last year's US championship, faced three break points in the match and never lost serve in the 61-minute rout.
"I love being back here, especially playing the night session," she said, despite having to wait until nearly midnight to begin her first-round match after a series of long contests on Arthur Ashe center court.
"A win is a win," said Wozniacki, aiming for her first Grand Slam title. "It doesn't really matter what time I get on.
"It's a great feeling. I was happy to be out there. I'm happy to be through to the second round."
Wozniacki advanced to a second-round match against Chang Kai-Chen of Taiwan, a straight sets 6-2 6-4 winner over Spain's Carla Suarez Navarro.