Finland’s Emil Ruusuvuori never lost his serve en route to a 6–4, 7–6 (3) win over second-seeded Hubert Hurkacz of Poland on Wednesday in the second round of the Citi Open in Washington. Ruusuvuori went 4-for-4 on break points on his own serve, and he converted his only break point on Hurkacz’s serve for a…