By SABC Sport
3rd June 2023
The Spaniard wasted little time in powering to a 6-1, 6-4, 6-2 victory, although there was a slight blip when he fell behind early in the second set.
Shapovalov's break only prompted Alcaraz to reel off seven games in a row, however, with match point following not long after.
"I knew I'd have my chances in the second set to come back a bit and that's what I did," Alcaraz said.
Alcaraz moves on to face Italian 17th seed Lorenzo Musetti, who handed British number one Cameron Norrie a 6-1, 6-2, 6-4 defeat.
The 20-year-old is bidding for his second Grand Slam title after winning the 2022 US Open and then missing this year's Australian Open through injury.
He remains on course for a semi-final showdown with Novak Djokovic, who had a challenging day but safely reached the fourth round with a hard-fought 7-6 (4) 7-6 (5) 6-2 over Alejandro Davidovich Fokina.
Elsewhere, Italian Lorenzo Sonego battled back from two sets down to upset Andrey Rublev 5-7, 0-6, 6-3, 7-6 (7/5), 6-3 in a clash that lasted three hours and 42 minutes.
Sonego will face Russian 11th seed Karen Khachanov, with the winner earning a possible quarter-final meeting with Djokovic.
"I played more aggressive than in the first and second sets because when he's aggressive it's tough to compete against him," he said.
Eleventh seed Khachanov advanced after defeating Australian Thanasi Kokkinakis 6-4, 6-1, 3-6, 7-6 (7/5) in an entertaining match-up.
Also still alive at Roland Garros is Greek star Stefanos Tsitsipas, who continued his bid for a maiden Grand Slam title with a 6-2, 6-2, 6-3 win over former semi-finalist Diego Schwartzman.
The Greek fifth seed, a finalist in Paris in 2021, will next play Austrian qualifier Sebastian Ofner.