Alcaraz took his time to find his rhythm on a windy night but eventually overcame veteran Croatian 6-4, 6-4, then took on Butler.

The 35-year-old guard, recently traded to the Golden State Warriors, opted not to stay by the Bay while it hosted Sunday's National Basketball Association All-Star Game. Instead he flew to the Gulf and was in the crowd to see Alcaraz win.

Butler then came on court. Both men donned microphones as they put on a short show for fans. Butler even attempted to return an Alcaraz lob with a between-the-legs shot - but missed.

Against the 36-year-old Cilic, Alcaraz was stronger at the pivotal moments. The first set turned on an 18-minute seventh game which ended with Alcaraz gaining the service break he needed.

In the second set, Alcaraz fell 0-40 behind on serve in the eighth game. He responded by taking 15 of the next 19 points to win the match in one hour, 38 minutes.

"I'm really pleased about saving that game," said Alcaraz on court. "Marin puts a lot of pressure when you're serving, he's a great returner. I'm really happy to stay calm in that moment, do my routine and make good shots. I'm really happy to win in two sets."

He will face Zhang Zhizhen or Luca Nardi in the second round.

Cilic was competing in his first event since knee surgery in November

Jiri Lehecka beat seventh seed Bulgarian Grigor Dimitrov 6-4, 6-4. It was the Czech's 11th victory in 2025, tied for the ATP Tour lead with Alex de Minaur and Miomir Kecmanovic.