Rafael Nadal opened his season by playing at the Brisbane International for the first time, where he reached the quarterfinals before losing to Milos Raonic in three sets.

Nadal made it to the final of the Abierto Mexicano Telcel without dropping a set, but was defeated by big-serving Sam Querrey.

In a rematch of the Australian Open final Nadal took on Federer in the fourth round of the Indian Wells Masters but again lost to his old rival.

However, Nadal bounced back by earning his third US Open title against first-time Grand Slam finalist Kevin Anderson, winning the final in straight sets.

At the Rolex Paris Masters he retired prior to his quarterfinal match against Filip Krajinović due to a knee injury.

He returned to the tour at the beginning of the grass-court season MercedesCup, where he suffered a shock defeat to 302nd ranked Tommy Haas in the second round despite holding match points, the lowest-ranked player to beat him since 1999.

He rebounded the following week by winning a record-extending ninth title at the Gerry Weber Open in Halle, doing so without the loss of a set and defeating Alexander Zverev in the final.

However, he bounced back by winning his lone title of the year at the Geneva Open defeating Mischa Zverev in the final in three sets.

He started his clay court season with third round exits at the Monte-Carlo Rolex Masters losing to Nadal and Barcelona Open, where he lost to qualifier Chung Hyeon in straight sets.

At the Italian Open, Zverev continued his excellent form by winning his first Masters event title when he defeated Novak Djokovic in straight sets.

Zverev began his grass-court season at the Ricoh Open as second seed and reached the semifinals, where he lost to eventual champion Gilles Müller.

In his next tournament, Zverev reached the final of the Gerry Weber Open for the second consecutive year, but lost to Roger Federer in only 53 minutes.

At the Wimbledon Championships, he achieved his best result at a Grand Slam event to date, falling in the fourth round to the previous years' runner up and 6th seed Milos Raonic in a five-set match.

He defeated South African Kevin Anderson in straight sets in the final to win his first ATP World Tour 500 event.

Despite his previous week's success, a fatigued Zverev lost in the second round of the Western & Southern Open to Frances Tiafoe in three sets.

Zverev started off the Asian swing with a quarterfinal appearance at the Shenzhen Open, losing to Damir Džumhur in straight sets.

He then suffered back-to-back loses in the quarterfinals of the Erste Bank Open to Jo-Wilfried Tsonga and the second round of the Rolex Paris Masters to Robin Haase On October 13, Dominic Thiem became the fourth qualifier.

In the quarter-finals, he met Stan Wawrinka, but Thiem would miss out on a first Masters 1000 semi-final, losing a final set tie-breaker.

At the beginning of the grass court season, Thiem reached the second round of the Gerry Weber Open, losing to Robin Haase.

In October, Čilić reached the semifinals of the Japan Open, Shanghai Rolex Masters and Swiss Indoors losing to Adrian Mannarino, Nadal and Juan Martín del Potro, respectively.

He then reached quarterfinals of the final regular event of the year the Rolex Paris Masters losing to Julien Benneteau Grigor Dimitrov had a flying start to the season winning the Brisbane International overcoming world No.

Dimitrov next moved on to play at the Australian Open, where he extended his winning streak further, reaching the semifinals being eliminated by Rafael Nadal in a five-set thriller, which lasted almost 5 hours.

The Bulgarian maintained his excellent start to the season, winning his second title of the year on home soil, defeating Belgian David Goffin in straight sets in the final.

Dimitrov then played in the Indian Wells Masters, losing in three sets to Jack Sock in the third round, after missing four match points.

The Bulgarian then had a good run at the Queen's Club Championships, where he reached the semifinals but lost in three sets to in-form eventual champion Feliciano López.

A week later, he recorded his first victory over Dimitrov in the quarterfinals of the Rotterdam Open and went on to reach his second-straight final, but lost in three sets to Jo-Wilfried Tsonga.

He then led Belgium to another Davis Cup victory against Australia in the World Group semifinals with four-set wins in both his singles rubbers against Nick Kyrgios and John Millman.

Jack Sock opened up the season with at the Hopman Cup with CoCo Vandeweghe where they reached the final but lost to the French team of Richard Gasquet and Kristina Mladenovic.

He then claimed his second title of the year at the Delray Beach Open after Milos Raonic withdrew from the final with a hamstring injury.

Sock finished the year strong by winning the biggest tournament of his career at the Rolex Paris Masters, defeating Filip Krajinović in the final.