The U.S. Open is underway, with the top storyline being Serena Williams, the No. 1 women’s player in the world, chasing a Grand Slam. Fans can live stream the matchups for free by clicking this link. Here are the top matches to look for on Day 1. Click here for the entire Day 1 schedule.

(1) Serena Williams vs. (86) Vitalia Diatchenko: 7 p.m. ET

Williams is the focus of this tournament, and 2015 has been one of the best years of her career. Pity poor Diatchenko, a 25-year-old from Russia who is just looking for a little love somewhere in the pro-Serena crowd.

“I hope somebody will support me,” Diatchenko said, according to The New York Times. “To play in New York, in the U.S., I’m alone here. I know my family will support me from TV, but I hope somebody will come and support me as well in the stadium.”

As the 86th-ranked player, she’s unlikely to have her request granted.

(1) Novak Djokovic vs. (89) Joao Souza 3 p.m. ET

In a similar mismatch, the top men’s player in the world is facing off with a 27-year-old Brazilian with zero tournament victories or finals appearances. Souza is 25-43, and 0-6 in Grand Slam events. Souza looks very much like a sacrificial lamb in the early going.

(8) Rafael Nadal vs. (33) Borna Coric 9 p.m. ET

Nadal will be a heavy favorite to defeat the Croatian Coric, but this is not such a mismatch as Djokovic vs. Souza. Coric is one match worse than .500 on the ATP World Tour, and is 4-4 in his Grand Slam matches. Coric only turned pro in 2013, and his stated career goal is to become No. 1. Beating Nadal today would be a superb start.

Nadal is known for his prowess on clay courts, but he’s devastating on hard surfaces as well. With a 344-101 record on hard courts, don’t expect an upset.

(25) Eugenie Bouchard vs. (57) Alison Riske 3 p.m. ET

Bouchard, of Canada, is the big name but Riske shouldn’t be dismissed. Riske has a WTA title under her belt from the Tianjin Open in 2014. Bouchard, just 21 years old, has no WTA titles yet but has put together several impressive runs in Grand Slam events. Last year Bouchard went to the semifinals of the Australian Open and the French Open before reaching the Wimbledon final.