Americans Coco Gauff and Jessica Pegula are onto Round 2 for doubles after the pair toppled Australia's Daria Saville and Ellen Perez, 6-3, 6-1.
Top American man Taylor Fritz challenges Kazakhstan's Alexander Bublik in their first round match.
Carlos Alcaraz defeats Hady Habib, 6-1, 603, in first round match
Germany's Angelique Kerber conquers Japan's Naomi Osaka in the pair's first round women's singles match. Keber notched three aces on her way to victory over the former world No. 1.
Rafael Nadal teamed with Carlos Alcaraz for the first time as Spain's dream team opened their doubles campaign with a 7-6, 6-4 defeat of Argentine sixth seeds Maximo Gonzales and Andres Molteni.
Carlos Alcaraz won his singles match on Monday despite some "pain," which he said would not prevent him from playing doubles with Rafael Nadal.