NEW YORK (Reuters) - Olympic champion Belinda Bencic put on a serving masterclass to beat Jessica Pegula 6-2 6-4 and reach the last 16 of the U.S. Open on Saturday.

The 11th-seeded Swiss won 85% of her first serve points and smacked four aces to improve to a 3-0 record against Pegula, including a victory over the American at the Tokyo Games that kicked off her gold medal-winning campaign.