Although most of the seeded players don't get started until the second round of the Miami Open, there were plenty of big names in action Wednesday.
Serena Williams was competing in her second singles tournament of the year but ended up with a first-round exit. Meanwhile, other players like Victoria Azarenka, Robin Haase and Jared Donaldson were all in action in the first round, trying to make a deep run in this key event.
There were several notable players in action in both the men's and women's draws, creating an exciting opening round from Key Biscayne, Fla.
Naomi Osaka def. Serena Williams; 6-3, 6-2
Victoria Azarenka def. Catherine Bellis; 6-3, 6-0
Ekaterina Makarova def. Timea Bacsinszky; 6-2, 2-6, 6-4
Alize Cornet def. Bethanie Mattek-Sands; 6-2, 7-5
Alison Riske def. Magda Linette; 1-6, 6-0, 6-2
Zarina Diyas def. Jennifer Brady; 7-5, 7-6(8)
No. 3 Garbine Muguruza def. Amanda Anisimova; ret.
Serena Williams reached the third round at Indian Wells earlier this month before suffering a loss to her sister, Venus, but she wasn't as fortunate this time around.
Naomi Osaka needed only two sets to beat the superstar, handing Williams her first American loss on hard court in 21 years, per the U.S. Open.
Williams didn't earn a single break and struggled throughout the day, although Osaka's win wasn't much of an upset based on her talent as the No. 22 player in the world.
"I was extremely nervous when I came on the court," Osaka said, per Live Tennis. "I kind of wanted to impress her."
Ben Rothenberg of the New York Times discussed the match and Williams' future:
Victoria Azarenka didn't have as much competition, cruising to a win against Catherine Bellis while dropping just three total games. Bellis won only 38 percent of service points all match as the former No. 1 player in the world was too tough to score against.
No. 14 seed Madison Keys could be in for a tough battle in the second round against Azarenka.
Alize Cornet had a little more trouble in Round 1 against Bethanie Mattek-Sands, but still earned a straight-set win thanks to a dominant effort with her serve. She now has a chance to keep it going against Anastasija Sevastova.
The only American who performed well in front of the home crowd was Alison Riske, who overcome an embarrassing 1-6 first set to win the next two with just two lost games. It wasn't her best game, but she stayed alive to take on Caroline Garcia.
Joao Sousa def. Ryan Harrison; 7-6(4), 7-6(4)
Robin Haase def. Yuichi Sugita; 6-4, 3-6, 6-1
Matthew Ebden def. Gilles Simon; 6-3, 6-7(2), 7-5
Jiri Vesely def. Lukas Lacko; 7-6(2), 6-3
Pierre-Hugues Herbert def. Taylor Fritz; 7-6(4), 6-4
Jeremy Chardy def. Rogerio Dutra Silva; 6-3, 7-6(2)
Benoit Paire def. Mischa Zverev; 1-6, 6-1, 6-2
Joao Sousa and Ryan Harrison both had the opportunity to make a deep run in this event, but only Sousa remains alive after a close win over the American.
The match featured two sets, both ending in a tiebreak with Sousa winning 7-4. While Harrison was a bit sloppy, the Portuguese star limited his unforced errors and finished with zero double faults. This represented a key difference in the narrow victory.
He will now face No. 7 David Goffin in the second round.
Another American, Taylor Fritz, failed to advance despite some solid play at the net:
Pierre-Hugues Herbert was simply better, earning a two-set victory to take on No. 2 Marin Cilic.
Gilles Simon had another disappointing exit after losing to Matthew Ebden in three sets. Ebden had seven aces and was extremely impressive defensively to keep Simon from advancing despite taking a set.
Of course, a few players did reach expectations in the first round.
Robin Haase had a tough time with Yuichi Sugita but left no doubts in the final set, winning 6-1 to earn a matchup against Juan Martin del Potro. Sugita struggles with his serve helped, finishing with one ace and seven double faults.
Jiri Vesely also reached the second round with a straight-set win over Lukas Lacko.
These players and more will get a chance to continue their strong play on Day 4 and beyond.