Six players to watch at the U.S. Open

It is difficult to accurately judge any player's level of fitness from only a few matches since the pro tennis tours resumed after a nearly six-month break because of the coronavirus pandemic. And many top players are skipping the U.S. Open for safety or injury reasons, making the fields shallower and more unpredictable. Here are six players to pay attention to beginning Monday.

Age: 33 • Country: Serbia • Rank: No. 1

Best Grand Slam result: 17-time champion

Scouting report: This appears to be Djokovic's tournament to lose. His top rivals, Rafael Nadal and Roger Federer, didn't make the trip to New York. The three of them have won the past 13 Grand Slam events, and Djokovic, owner of 17 major titles overall, also hasn't lost in 23 matches this year. But while he is fully recovered from a bout with COVID-19 in June, he seemed bothered by a neck injury in last week's warmup event and has been distracted in recent days leading a movement to form a players association.

Age: 29 • Country: Canada • Rank: No. 30

Best Grand Slam result: 2016 Wimbledon final

Scouting report: It is tempting to say this could be the tournament to break up the Big Three's reign. But who would do it? Dominic Thiem and Daniil Medvedev, who have each played in Grand Slam finals the past two seasons, are seeded No. 2 and No. 3, but Raonic is playing the best since the tour restarted. He reached the final of the warmup event last week, dominating Djokovic early before losing in three sets.

Best Grand Slam result: Three-time champion

Scouting report: He is not likely to contend for the title, but that Murray is playing singles in a Grand Slam tournament at all is worth noting. He last competed for a major singles title at the 2019 Australian Open. After he lost in the first round, it seemed his retirement was imminent. A second hip surgery followed, and Murray returned to the tour six months later, playing mostly doubles and best-of-three-set singles. He beat a top-10 player, Alexander Zverev, last week, but how his body fares in a best-of-five-set tournament will be interesting to track.

Age: 22 • Country: Japan • Rank: No. 10

Best Grand Slam result: Two-time champion

Scouting report: Six of the top eight women in the rankings, including defending champion Bianca Andreescu, did not enter the U.S. Open. The No. 1 seed is Karolina Pliskova, who has never won a Grand Slam singles title, and No. 2 is Sofia Kenin, the 21-year-old American who was the surprise champion at the Australian Open in January. So a recent U.S. Open champion like Osaka could be considered a favorite. She would certainly have eyes on her after she joined the widespread sports protests over the shooting of Jacob Blake in Kenosha, Wis. But after reaching the final of the warmup event last week, she withdrew with a hamstring injury sustained in her semifinal match.

Best Grand Slam result: 23-time champion

Scouting report: Williams is once again taking aim at Margaret Court's record of 24 Grand Slam singles titles. Williams can never be counted out even as she approaches her 39th birthday next month. She hasn't won a Grand Slam singles title in 3½ years, but she has been a finalist four times in that span. In her two tournaments this month leading up to the Open, Williams is 3-2.

Age: 37 • Country: Belgium • Rank: None

Best Grand Slam result: Four-time champion