Gasquet had never defeated the Spaniard in seven previous tries and did not come close in the early afternoon match on Court Central in Monaco either, although he managed to put Nadal under some pressure late in the second set.
After tiring himself out with heavy-topspin exchanges in the first set, Gasquet found more success with riskier play in the second set but lacked the consistent firepower to worry the six-time Monte Carlo champion.
The statistics told the story, as Nadal won a higher percentage of both first- and second-serve points and faced just one break point, although the Frenchman was able to capitalize on that chance to even the score at 4-4 in the second set.
Two double faults were among the few blemishes on an otherwise commanding performance by the world No. 1, who immediately broke back and then served out the match on his first opportunity.
Nadal leads the head-to-head 5-2, although Ljubicic upset the Spaniard in three sets in their most recent match last year in Indian Wells, California. In other action Thursday involving Spanish players, David Ferrer easily advanced with a 6-1, 6-3 win over big-serving Canadian Milos Raonic and Tommy Robredo retired with a left adductor injury while leading Serbia's Viktor Troicki 6-3, 1-2.
Ferrer and Troicki will square off in one of four quarterfinal matches on Friday. Champions of the Monte-Carlo Rolex Masters, one of the biggest clay-court events on the ATP Tour calendar, often use it as a springboard for success at the French Open, which gets underway in late May.
Nadal won his sixth Monte Carlo title last year to kick off an incredible run that included capturing his fifth French Open title, second Wimbledon crown and first-ever U.S. Open title and taking back the No. 1 ranking. The Spaniard shares the record for most Monte Carlo titles with Britain's Reginald "R.F." Doherty, who won the tournament six times between 1897 and 1904.