Alcaraz gets a lock-up tour at Alcatraz, Svitolina and Kostyuk celebrate a landmark win, as Federer hits the links with Ruud and Zverev

In a new "Daily Dose of Social Media," the Laver Cup is in its final stages of preparation. Carlos Alcaraz arrived in San Francisco and visited Alcatraz Island during a media day, while Roger Federer welcomed Alexander Zverev, Casper Ruud, and Alcaraz himself for a relaxing day on the golf course.

Meanwhile, Elina Svitolina and Marta Kostyuk celebrated Ukraine's historic win over Spain and their advance to the Billie Jean King Cup semifinals with photos on their social media. Elsewhere, Joao Fonseca thanked his captain, Andre Agassi, and visited the San Francisco Giants' stadium with his Team World colleagues.

Elina Svitolina and Marta Kostyuk took to social media to celebrate Ukraine's historic win at the Billie Jean King Cup Finals, where they reached the tournament semifinals for the first time ever. In the first match of the day, Marta Kostyuk delivered a hard-fought 7-6(3), 6-2 victory over Spain's No. 2, Jessica Bouzas Maneiro. "Stronger together on the way to the semis," the world No. 28 posted after securing the first win for her team.

The joy for the Ukrainians was even greater when, in the second match, Elina Svitolina fulfilled her duty and defeated former world No. 2 Paula Badosa, who was making her return to the courts after two months away. Badosa put up a good fight, taking the first set, but Svitolina ultimately won the match 5-7, 6-2, 7-5, giving Ukraine the tie and a spot in the semifinals without needing to play doubles. Svitolina posted, "UKRAINE, this is for you. For the first time in history, we're in the team world championship semifinals. We're proud to represent our country at the highest level and thank everyone for the powerful support! Ukraine—above all!"

With just one day to go until the start of the Laver Cup, the host is the 20-time major champion Roger Federer, one of the driving forces behind the tournament's creation who remains part of the organizing team. The former world No. 1 welcomed some of the Team Europe players to a golf course, where he was joined by Casper Ruud and Alexander Zverev.

However, perhaps the photo that drew the most attention was one with Carlos Alcaraz, who arrived at the Laver Cup as the new world No. 1 and the main star for the Europeans. Federer also spent time with Alcaraz on the golf course. The Spaniard participated in promotional activities ahead of the tournament, including a visit to Alcatraz Island in San Francisco, where he even went inside the prison and took several photos before the event.

Joao Fonseca thanked Team World's captain, Andre Agassi, and vice-captain, Pat Rafter, for the days they have trained together in the lead-up to the Laver Cup. The 18-year-old Brazilian star is preparing for his debut defending Team World, where he will join colleagues like Francisco Cerundolo, Taylor Fritz, and Alex De Minaur in the quest to bring a title back to Team World.

"Extremely grateful for the opportunity to learn from the best this week. Thanks, @agassi and Pat! I'm very happy to be able to learn from these tennis legends this week here at the Laver Cup. Thank you, Agassi and Pat!"

During promotional activities, Team World visited the home stadium of the MLB's San Francisco Giants, where they received jerseys from the local baseball team's players. The team visited Oracle Park and even played baseball on the main field, with Cerundolo, rEilly Opelka, Alex Michelsen, Jenson Brooksby and the vice captain former No. 1 Pat Rafter.