Nadal lost just two games in routing Thiem and will now face Grigor Dimitrov in the semifinal.
MONACO (AP) Rafael Nadal won nine straight games to open his match against Dominic Thiem, quickly advancing to the semifinals of the Monte Carlo Masters with a 6-0, 6-2 victory on Friday.
The top-ranked Spaniard is on course for a record-extending 11th Monte Carlo title.
Thiem, an Austrian who is seeded fifth and beat Nadal twice before on clay, earned sympathetic cheers from the crowd when he finally won a game in the second set.
Nadal will next face Grigor Dimitrov. The fourth-seeded Bulgarian beat No. 6 David Goffin 6-4, 7-6 (5) in an error-strewn match.
Goffin led 4-0 in the second set but the Belgian missed three set points at 5-4.
Later Friday, second-seeded Marin Cilic was to play Kei Nishikori and No. 3 Alexander Zverev was facing Richard Gasquet.