Once the opening ceremony for the 2024 Paris Olympics is over, competition begins in earnest all across France.

There are plenty of gold medals at stake on Saturday. There's swimming and tennis all day long. And several stars will be in action. Here are the biggest storylines to follow on the first full day of action.

Fiji goes for a third straight Olympic gold in rugby sevens

Rugby sevens got an early start before the opening ceremony, and back-to-back champion Fiji looks on track for a third straight gold medal. It cruised through pool play and came back to beat Ireland in the quarterfinals. Fiji will face Australia, and South Africa goes against France in the semifinals. The gold-medal match will take place Saturday evening.

Gold is also at stake in men's street skating, with Japan's Yuto Horigome looking to defend his 2020 medal.

Team USA star Coco Gauff makes Olympic debut in tennis

Team USA's female flag-bearer Coco Gauff will make her Olympic debut in tennis doubles. Gauff and teammate Jessica Pegula will face Australia's Ellen Perez and Daria Saville on Court 14 at Roland Garros.

Gauff, ranked No. 2 in the world, will participate in three events: singles, doubles and mixed doubles, all set to start over the next few days.

Also Saturday, Japan's Naomi Osaka faces Germany's Angelique Kerber; 24-time Grand Slam champion Novak Djokovic takes on Australia's Matthew Ebden; and Spain's Carlos Alcaraz and Rafael Nadal will play a doubles match against Argentina's Maximo Gonzalez and Andres Molteni during the night session.

Katie Ledecky leads Team USA swimming in 400 freestyle

Katie Ledecky will open her fourth Olympics in the 400-meter freestyle at Paris La Defense Arena. She'll swim in Heat 3 in the qualifying race. If she makes it through, Ledecky will go for her eighth Olympic gold medal in the final Saturday night. The eight fastest times from the heats qualify for the final.

Ledecky, who holds the 400 freestyle Olympic record, will need to beat out current world record holder Ariarne Titmus of Australia. Titmus defeated Ledecky in the event in Tokyo. She also will swim in Heat 3. Canadian phenom Summer McIntosh is also a name to watch.

Wemby, Antetokounmpo highlight star-studded basketball slate

NBA star Victor Wembanyama and Team France will open their Olympic slate against Brazil at Pierre Mauroy Stadium in Lille. The 20-year-old Wembanyama and Rudy Gobert hope to lead France past Team USA for gold. The hosts lost the gold-medal game to the U.S. in Tokyo.

Elsewhere, NBA champion Giannis Antetokounmpo and Greece will face Canada. The Canadian team also could challenge the U.S. for gold. It has a talented roster featuring NBA champion Jamal Murray and Shai Gilgeous-Alexander.

Argentina soccer looks to reset after chaotic opener

Argentina soccer will continue group play against Iraq, hoping to reset after a wild opener. Morocco beat Argentina 2-1 on Wednesday in a match delayed by two hours after fans invaded the pitch.

Argentina needs a win to boost its chance of advancing to the knockout stage. Only the top two teams from each group will move on. Argentina hasn't won Olympic gold since doing it consecutively in 2004 and 2008.