The Western & Southern Open continued first-round play Monday with several notable players struggling in their opening matches.
The Masters event usually features the biggest stars in the sport as one of the final lead-ups to the U.S. Open. However, the field is lighter than usual this year with Andy Murray, Stan Wawrinka and Novak Djokovic all out with injuries. Roger Federer withdrew from the event Monday.
Fortunately, there is still enough talent in both the men's and women's draws to keep fans entertained in Cincinnati.
Here is a look at the latest action from the hard-court tournament.
Richard Gasquet def. John-Patrick Smith; 6-4, 6-4
Ivo Karlovic def. Jiri Vesely; 6-3, 3-6, 7-5
Fabio Fognini def. Daniil Medvedev; 7-6 (5), 6-4
Tommy Paul def. Donald Young; 6-4, 7-6 (4)
Frances Tiafoe def. Maximilian Marterer; 6-3, 7-6 (2)
Feliciano Lopez def. Hyeon Chung; 7-6 (5), 6-1
Mitchell Krueger def. Benoit Paire; 6-2, 6-1
Joao Sousa def. Kyle Edmund; 6-3, 2-6, 6-3
No. 15 Sam Querrey def. Stefan Kozlov; 6-3, 6-0
Mischa Zverev def. Fernando Verdasco; 6-4, 6-4
Ramkumar Ramanathan def. Christopher Eubanks; 6-7 (5), 6-1, 6-4
Camila Giorgi def. Katerina Siniakova; 6-2, 6-2
Daria Gavrilova def. No. 13 Kristina Mladenovic; 6-0, 7-6 (6)
Beatriz Haddad Maia def. Lauren Davis; 6-3, 6-2
Lesia Tsurenko def. Anastasia Pavlyuchenkova; 5-7, 7-6 (6), 6-0
No. 14 Petra Kvitova def. Anett Kontaveit; 1-6, 7-6 (2), 6-3
Kiki Bertens def. Oceane Dodin; 6-3, 6-0
Roberta Vinci def. Timea Babos; 7-5, 7-5
Taylor Townsend def. Monica Puig; 3-6, 6-3, 6-2
Yulia Putintseva def. Veronica Cepede Royg; 6-4, 3-6, 6-3
Daria Kasatkina def. Aliaksandra Sasnovich; 6-4, 6-2
No. 16 Madison Keys def. Coco Vandeweghe; 6-4, 3-6, 6-3
Carla Suarez Navarro def. Mirjana Lucic-Baroni; 6-3, 7-5
Madison Keys Survives Battle Against CoCo Vandeweghe
This wasn't necessarily the typical seeded vs. unseeded matchup in the first round with Madison Keys ranked No. 17 in the world entering the week and CoCo Vandeweghe ranked No. 21. The duo also snuck in a hug the last time they played in the Stanford final.
The close battle lived up to expectations with an exciting back-and-forth battle that saw Keys escaping with a three-set win.
Keys was not afraid to go after her opponent in the return game, approaching the net on this shot:
The American was also extremely consistent with her serve, winning 70 percent of her points on the first serve and 67 percent on the second serve. Vandeweghe couldn't match and hurt herself with seven double faults and zero aces.
After the match, Keys discussed her enjoyment playing in Cincinnati.
"This is one of my favorite events of the year because I'm from the Midwest," she said, per the event's official account. "It's like coming home."
The comfort level helped her advance to the second round, where she will take on Daria Kasatkina.
Sam Querrey Gets off to Hot Start
Jack Sock, John Isner and Sam Querrey are close in the world rankings, but Querrey has been in the best form of any American and has a chance to make a deep run on his home soil this week.
The 29-year-old showcased his skill in the first round Monday with an easy win over Stefan Kozlov.
Querrey earned five aces with zero double faults to win the first set 6-3, then was even more dominant while putting up a bagel in the second set.
Overall, the American won 78 percent of his service points and didn't face a single break point in the entire match.
He will now taken on the winner of Robin Haase and Adrian Mannarino with No. 2 seed Dominic Thiem looming before the quarterfinals.
Kristina Mladenovic Goes Down
There weren't a lot of high seeds in action Monday, but No. 13 seed Kristina Mladenovic competed and ended up being the only one eliminated.
Daria Gavrilova came out extremely aggressive and jumped over the French star, earning a dominant 6-0 win in the first set. Mladenovic fought harder in the second set and forced a tiebreak but couldn't keep up at the end and fell 7-6, including an 8-6 tiebreak.
The final point wasn't an easy one, but the underdog came through when needed:
At No. 26 in the world, Gavrilova was a difficult opening matchup for any seeded player. However, Mladenovic didn't help her case with six double faults and plenty of unforced errors. She only won 44 percent of her service points as she faced an excellent return game from the Australian.
In a relatively calm day, the straight-set upset was the biggest surprise in Cincinnati.
Tuesday Schedule (Full order of play available at ATPWorldTour.com)
Juan Martin del Potro vs. No. 10 Tomas Berdych
No. 13 Jack Sock vs. Yuichi Sugita
No. 14 John Isner vs. Tommy Paul
Steve Johnson vs. David Ferrer
No. 3 Dominic Thiem vs. Fabio Fognini
No. 9 David Goffin vs. Nick Kyrgios
Jared Donaldson vs. No. 12 Roberto Bautista Agut
Ivo Karlovic vs. No. 8 Jo-Wilfried Tsonga
Kevin Anderson vs. Alexandr Dolgopolov
No. 11 Pablo Carreno Busta vs. Paolo Lorenzi
Albert Ramos-Vinolas vs. Mikhail Youzhny
Robin Haase vs. Adrian Mannarino
Diego Schwartzman vs. Karen Khachanov
Nikoloz Basilashvili vs. Borna Coric
No. 9 Venus Williams vs. Alison Riske
No. 4 Garbine Muguruza vs. Beatriz Haddad Maia
Ana Konjuh vs. No. 11 Dominika Cibulkova
Taylor Townsend vs. No. 2 Simona Halep
Sloane Stephens vs. Lucie Safarova
Julia Goerges vs. No. 10 Agnieszka Radwanska
No. 7 Johanna Konta vs. Kiki Bertens
Alize Cornet vs. Catherine Bellis
Elena Vesnina vs. Caroline Garcia
Ekaterina Makarova vs. Barbora Strycova
Ashleigh Barty vs. Varvara Lepchenko
Francoise Abanda vs. Magda Linette
No. 12 Jelena Ostapenko vs. Aleksandra Krunic
Donna Vekic vs. Natalia Vikhlyantseva
No. 15 Anastasija Sevastova vs. Shuai Peng