2018 US Open Series
In tennis, the 2018 US Open Series was the fifteenth edition of the US Open Series, which comprises]d a group of hard court tournaments that started on July 23, 2018 in Atlanta and concluded in Connecticut for the women and in Winston-Salem for the men on August 26, 2018. This edition consisted of three separate men's tournaments and three women's tournaments, with the Western & Southern Open hosting both a men's and women's event. The series was headlined by two ATP World Tour Masters 1000 and two WTA Premier 5 events.
Tournament Schedule
| Week | Date | Men's Events | Women's Events |
| 1 | July 23 – July 29 | Atlanta BB&T Atlanta Open 2018 Champion:  John Isner | No Series Event Held This Week |
| 2 | July 30 – August 5 | No Series Event Held This Week | San Jose Silicon Valley Classic 2018 Champion:  Mihaela Buzărnescu |
| 3 | August 6 – August 12 | Toronto Rogers Cup presented by National Bank 2018 Champion:  Rafael Nadal | Montreal Rogers Cup presented by National Bank 2018 Champion: Simona Halep |
| 4 | August 13 – August 19 | Cincinnati Western & Southern Open 2018 Champion:  Novak Djokovic | Cincinnati Western & Southern Open 2018 Champion:  Kiki Bertens |
| 5 | August 20 – August 26 | Winston-Salem Winston-Salem Open 2018 Champion:  Daniil Medvedev | New Haven Connecticut Open 2018 Champion:  Aryna Sabalenka |
| 6–7 | August 27 – September 9 | New York US Open 2018 Champion: Novak Djokovic | New York US Open 2018 Champion:  Naomi Osaka |
Week 1
ATP – BB&T Atlanta Open
was the defending champion and successfully defended his title, defeating Ryan Harrison in a rematch of the 2017 final, 5–7, 6–3, 6–4.Main Draw Finals
Week 2
WTA – Silicon Valley Classic (San Jose)
was the defending champion, but withdrew due to a wrist injury.Mihaela Buzărnescu won her first WTA Tour singles title, defeating Maria Sakkari in the final, 6–1, 6–0.
Main Draw Finals
Week 3
ATP – Rogers Cup (Toronto)
was the defending champion, but lost in the quarterfinals to Stefanos Tsitsipas.Rafael Nadal won his fourth Rogers Cup title, defeating Tsitsipas in the final, 6–2, 7–6.
Main Draw Finals
WTA – Rogers Cup (Montreal)
was the defending champion, but she lost to Sloane Stephens in the semifinals.World No. 1 Simona Halep won the title, defeating Stephens in the final, 7–6, 3–6, 6–4.
Main Draw Finals
Week 4
ATP – Western & Southern Open (Cincinnati)
was the defending champion, but lost to Novak Djokovic in the third round.Djokovic won the title, defeating Roger Federer in the final, 6–4, 6–4, becoming the first player to win all nine ATP Masters 1000 events since its inception in 1990.
Main Draw Finals
WTA – Western & Southern Open (Cincinnati)
was the defending champion, but lost in the second round to Lesia Tsurenko.Kiki Bertens won her first hard court & Premier 5 level title by beating Simona Halep in the final, 2–6, 7–6, 6–2.
Main Draw Finals
Week 5
ATP – Winston-Salem Open
was the defending champion but chose not to participate this year.Daniil Medvedev won the title, defeating Steve Johnson in the final, 6–4, 6–4.
Main Draw Finals
WTA – Connecticut Open (New Haven)
was the defending champion, but lost to Aryna Sabalenka in the second round.Sabalenka went on to win her first WTA Tour title, defeating Carla Suárez Navarro in the final, 6–1, 6–4.
Main Draw Finals
Weeks 6–7
ATP – US Open (New York)
was the defending champion, but retired in his semifinal match against Juan Martín del Potro.Novak Djokovic won the title, his third at the US Open and 14th Grand Slam title overall, tying Pete Sampras, defeating del Potro in the final, 6–3, 7–6, 6–3.
Main Draw Finals
WTA – US Open (New York)
was the defending champion, but lost to Anastasija Sevastova in the quarterfinals.Naomi Osaka won the title by defeating Serena Williams in the final, 6–2, 6–4.