Andy Abeyta/The Desert Sun / USA TODAY NETWORK

Top seed Taylor Fritz opened his title defense at the Japan Open with a 6-4, 6-3 first-round win over Cameron Norrie of Great Britain on Tuesday in Tokyo.

The American struck 13 aces to advance to the second round in one hour, 21 minutes. Fritz and Norrie are longtime rivals, with Fritz now moving ahead 7-6 in their career matchups.

Second seed Casper Ruud of Norway also moved on with a 7-6 (6), 6-3 win over Japan's Yosuke Watanuki, but two other seeds fell at the ATP 500 event. Russian Aslan Karatsev ousted sixth seed Frances Tiafoe 6-3, 7-6 (4), and another Russian, seventh-seeded Karen Khachanov, was defeated by Australian Alexei Popyrin 6-4, 6-2.

Diego Schwartzman defeated Francisco Cerundolo 6-4, 6-1 in an all-Argentina battle, and Japan's Shintaro Mochizuki knocked out another Argentine, Tomas Martin Etcheverry, 6-4, 7-6 (5). Up-and-coming American Ben Shelton came back to top Taro Daniel of Japan 3-6, 6-4, 7-6 (2).

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