The Briton confirmed resilience within the early levels by staving off 5 break factors in her opening service recreation.
She then wrapped up the opening set in fashion by successful 5 successive video games.
After exchanging a few breaks within the second set, Raducanu – who additionally beat Ruse in Auckland in 2024 – discovered the essential break to steer 5-4 and served out for the match.
Since dropping in opposition to Aryna Sabalenka at Wimbledon earlier in July, Raducanu has bounced again strongly with 4 victories from 5 appearances on exhausting courts.
If she will get previous Stearns in Montreal, American fifth seed and 2025 Wimbledon finalist Amanda Anisimova may very well be ready within the third spherical.
Boulter narrowly averted being on the tip of a bagel in opposition to Zarazua, saving two set factors to get to 5-1, however the Mexican swiftly wrapped up the opener when again on serve.
The 28-year-old put up higher resistance within the second however by no means managed to get a foothold within the match as she crashed out.