Luis M. Alvarez/Associated Press

The competition continues to heat up at the Miami Open, with most of the top players in action Monday.

Quarterfinal spots were on the line in the women's draw, while the men still needed to fill up the round of 16. The top seeds in both fields faced tough battles and not all survived.

Big names like Roger Federer, Stan Wawrinka, Venus Williams and Angelique Kerber fought to stay alive in the Masters 1000 tournament, leading to a fun day of tennis in South Florida.

Here is what you need to know from Monday's matches.

Scores

Miami Open Results - Monday, March 27 Men's Singles Score No. 4 Roger Federer def. No. 29 Juan Martin del Potro 6-3, 6-4 No. 10 Tomas Berdych def. No. 24 Gilles Muller 6-3, 6-4 No. 14 Roberto Bautista Agut def. No. 22 Sam Querrey 3-6, 6-2, 6-3 Adrian Mannarino def. Borna Coric 6-2, 2-6, 7-6(3) No. 12 Nick Kyrgios def. No. 17 Ivo Karlovic 6-4, 6-7(4), 7-6(2) No. 16 Alexander Zverev def. No. 18 John Isner 6-7(5), 7-6(7), 7-6(5) No. 8 David Goffin def. Diego Schwartzman 4-6, 6-3, 7-5 No. 1 Stan Wawrinka def. Malek Jaziri 6-3, 6-4 Women's Singles Score No. 1 Angelique Kerber def. Risa Ozaki 6-2, 6-2 No. 2 Karolina Pliskova def. No. 15 Barbora Strycova 6-1, 6-4 Lucie Safarova def. No. 4 Dominika Cibulkova 7-6(5), 6-1 No. 12 Caroline Wozniacki def. No. 6 Garbine Muguruza 7-6(1), ret. No. 26 Mirjana Lucic-Baroni def. Bethanie Mattek-Sands 7-5, 6-4 No. 10 Johanna Konta def. Lara Arruabarrena 7-5, 6-1 No. 3 Simona Halep def. No. 14 Samantha Stosur 4-6, 7-5, 6-2 No. 11 Venus Williams def. No. 7 Svetlana Kuznetsova 6-3, 7-6(4) MiamiOpen.com

The updated men's draw is available at ATPWorldTour.com, while the women's draw is available at WTATennis.com.

Schedule

Order of Play - Tuesday, March 28 Stadium Draw Matchup Time (ET) ATP No. 2 Kei Nishikori vs. Federico Delbonis 11 a.m. WTA No. 2 Karolina Pliskova vs. No. 26 Mirjana Lucic-Baroni 1 p.m. ATP No. 5 Rafael Nadal vs. Nicolas Mahut Next ATP No. 4 Roger Federer vs. No. 14 Roberto Bautista Agut Next WTA No. 12 Caroline Wozniacki vs. Lucie Safarova 7:30 p.m. ATP No. 12 Nick Kyrgios vs. No. 8 David Goffin 9 p.m. Grandstand ATP Fabio Fognini vs. Donald Young 10:50 a.m. ATP No. 13 Jack Sock vs. Jared Donaldson Next ATP No. 11 Tomas Berdych vs. Adrian Mannarino Next ATP No. 2 Stan Wawrinka vs. No. 16 Alexander Zverev 5 p.m. MiamiOpen.com

Monday Recap

A lot of the drama from earlier in the day came in the women's portion of the tournament.

No. 6 Garbine Muguruza was eliminated after she retired during her match against No. 12 Caroline Wozniacki. Per the Associated Press (h/t USA Today), it was a heat-related illness that ended her day.

Considering it took an hour and 15 minutes for Wozniacki to win the first set, exhaustion likely set in.

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She wasn't the only top-10 seed to go down, though, as Lucie Safarova knocked off No. 4 Dominika Cibulkova.

WTA showed some of the all-around effort required to pull off the upset:

Safarova had nine aces compared to just one from Cibulkova, and the underdog actually won 51 percent of return points. This is a good recipe for success, and she will try to keep it up against Wozniacki in the quarterfinals.

Venus Williams helped continue the trend by defeating No. 7 Svetlana Kuznetsova in the last match of the day. The American was aggressive with her serves and it helped lead to a straight-set win, eliminating the third top-10 player on the day.

Simona Halep almost suffered the same fate in a tough battle against Samantha Stosur. The No. 3 seed lost the first set and needed an extra game in the second just to keep the match alive. She eventually got back on track in the third with a 6-2 win to stay alive.

No. 1 Angelique Kerber and No. 2 Karolina Pliskova didn't have the same problems as both were able to earn relatively easy straight-set victories.

Kerber was especially impressive, using her forehand to earn some winners:

With just nine combined losses in the two matches, however, the top two seeds look like they are the clear favorites at this stage of the tournament.

The men's side of the tournament is a bit more open, although Roger Federer continues to show why he is again a top contender.

The veteran was in classic form while tallying seven aces with zero double faults, also winning 83 percent of his first-serve points. Juan Martin del Potro is not a walkover, but he had a tough time keeping up in this one.

After it seemed as though Federer's time as a top contender was over, he has been on a ridiculous hot streak this season:

He could be a threat for No. 1 Stan Wawrinka, who also had an easy time in the third round win over Malek Jaziri. He won all six break points he faced and otherwise avoided mistakes in a quality performance.

Crowd favorite Sam Querrey appeared ready to join them in the next round after a 6-3 win in the first set against Roberto Bautista Agut. Unfortunately, the momentum shifted quickly and it led to a three-set loss for the American.

Both players struggled with accuracy in this one, but Querrey could only save eight of the 15 breaks he faced, and that much pressure doesn't usually lead to great results.

John Isner was also eliminated Monday in arguably the best match of the day. He and Alexander Zverev battled to a tiebreak in all three sets, but Zverev showed excellent resolve to earn the win. Steve Tignor of Tennis Magazine described the German's effort:

Even with 28 aces, Isner couldn't get the key points when it mattered.

The good news is there are still a few more Americans remaining for the Miami fans to cheer for going forward.

Statistics courtesy of MiamiOpen.com.