Big names fell early and unexpected teams broke through to steal the spotlight on Day 1 of U.S. Open mixed doubles play, headlining an electric opener packed with upsets and standout performances.

The US Open's revamped mixed doubles tournament sees only one true doubles partnership, which has thus far breezed through the draw in New York.

The No. 1-ranked Sinner, the defending champion in singles at Flushing Meadows, was supposed to compete in mixed doubles with Katerina Siniakova.

Carlos Alcaraz won the Cincinnati Open title in a little more than 20 minutes after top-ranked Jannik Sinner was forced to retire because of illness during the first set