The Miami Open had already lost its share of the men's singles tennis stars in the early rounds of the ATP tournament, and has now lost two more of the world's best, as both Andy Murray and Serena Williams both fell in upsets on Monday.

Women's tennis' top ranked player fell in three sets to Svetlana Kuznetsova 6-7 (3), 6-1, 6-2. The loss ended Williams' 20-match winning streak at the Miami event, as she was looking to pick up her fourth consecutive title.

"I did the best I could," said Williams following the match. "I can't win every match. These players come out and play me like they've never played before in their lives. I have to be 300 percent every day."

Williams has not won a tournament since winning at Cincinnati this past August, and was coming off a difficult finals loss at Indian Wells last week. Williams struggled on the court committing 55 unforced errors to Kuznetsova's 18. The 19th-ranked Russian moves onto the quarterfinals to face the 31st-ranked Ekaterina Makarova who is coming off a straight sets match win over Elina Svitolina 6-1, 6-4.

While the WTA lost its biggest star in the Miami Open Monday, men's singles tennis lost another one of the top five in the world, as second ranked Andy Murray lost in three straight sets to 28th-ranked Grigor Dimitrov 6-7 (1), 6-4, 6-3. It's the second straight tournament that Murray has been knocked out in the third round, and leaves the world's second-ranked men's tennis player with just two ATP Tour wins since losing to Novak Djokovic in the Australian Open in January.

"(I made) a lot of unforced errors in the third set," said Murray following the loss. "Obviously, I didn't start the second set particularly well. After winning a close first set you want to try and put your opponent under pressure. I think I lost my first two service games to love, so that wasn't very good. Then in the third set, he managed to get up a break and then I made a lot of unforced errors. Credit to him. He was more solid than me."

Dimitrov now faces 16th-ranked Gael Monfils in the round of 16, and is looking to get his first win over Frenchman since 2014. The Miami Open now only has one of the top five men's tennis players left in the tournament with top-ranked Djokovic facing 14th-ranked Dominic Thiem on Tuesday.