NEW YORK - Defending champion Carlos Alcaraz made an emphatic re­turn to Grand Slam action af­ter a 139-day absence, defeat­ing Russia’s Roman Safiullin in straight sets on Monday, while Aryna Sabalenka opened her bid for a historic third consecu­tive US Open title with a com­fortable victory.

Second seed Alcaraz, whose fitness had been a major talk­ing point following a lengthy layoff caused by a wrist injury, showed little sign of rust as he beat Safiullin 6-4, 6-4, 6-4 at Arthur Ashe Stadium. “It’s al­most four-and-a-half months. You don’t know what’s going to happen in your body, in your mind, everything,” Alcaraz said. “I just tried to play one game at a time, enjoy the points and feel the love from the people.”

Alcaraz’s successful come­back assumes greater signifi­cance after Novak Djokovic’s shock first-round defeat on Sunday, while world No. 1 Jan­nik Sinner remains absent through injury, leaving the Spaniard among the leading contenders in the men’s draw.

Earlier, Sabalenka began her title defence with a 6-2, 6-4 win over Colombia’s Camila Osorio. The world No. 1, seeking a third straight crown in New York, advanced to a second-round meeting with Russia’s Polina Iatcenko. “I’m happy with my performance,” Sabalenka said after ending a difficult spell in which she has not reached a final since completing the Sun­shine Double in March.

Last year’s runner-up Amanda Anisimova also progressed, cel­ebrating her 25th birthday with a 6-1, 6-3 victory over fellow American Ashlyn Krueger. The daay’s major upset came from Stefanos Tsitsipas, who defeated 10th seed and recent Cincin­nati champion Arthur Fils 4-6, 7-6(3), 6-1, 6-4. The Greek said the victory had given his con­fidence a much-needed boost. Former champion Iga Swiatek eased past China’s Wang Xiyu 6-2, 6-3, while Wimbledon final­ist Karolina Muchova beat Sinja Kraus 6-3, 6-0. American hopes were strengthened by victo­ries for Emma Navarro, Taylor Townsend, Ben Shelton and Fran­ces Tiafoe. China’s Zheng Qinwen also advanced with a comeback win over Kristina Liutova.

Meanwhile, former champion Stan Wawrinka’s final US Open appearance ended in a straight-sets defeat by Italy’s Matteo Berrettini. The 41-year-old Swiss is set to retire at the end of the season. Naomi Osaka also moved into the second round, overcoming Anastasia Zakharo­va 7-6(6), 7-6(3), as the tourna­ment’s star-studded field con­tinued to produce compelling action in New York.