Perhaps the biggest news of the past week was the sudden retirement of Novak Djokovic in Dubai. The world No. 1, already down a set to Feliciano Lopez, quit in the second, citing an eye infection that had plagued him all week.
Djokovic expects to be ready for Indian Wells late next week.
Here's what else was on our writers' minds in the latest edition of Racket Response.
@CarlBialik: The Big Four are idle or ailing. Novak Djokovic has an eye infection, Roger Federer has delayed a return from knee surgery, Andy Murray is getting to know his 3-week-old daughter, Sophia, and Rafael Nadal has failed to reach the final of six of his past eight clay-court tournaments.
With the men who follow the game's elite foundering as well, tennis is ripe for a takeover by youngsters.
Dominic Thiem, a 22-year-old from Austria, is leading the charge -- the same Thiem who beat Nadal at the Argentina Open two weeks ago.
You haven't heard much from Thiem if you're mostly paying attention to the Grand Slams. He has reached the fourth round of a major just once. Perhaps Thiem's shortcomings in majors are because he usually plays the week before Slams instead of resting and practicing. But in little-known tour stops in between, Thiem has been thriving.
This past weekend, he won his second title this month, on Acapulco's hard courts, his first trophy on a surface on which he hadn't even reached a semi until last September. Thiem entered the month with one top-10 win -- now he has three. He is ranked 14th, higher than anyone else under age 25 and closer in ranking points to No. 10 than to No. 15. And he is third in the race to year-end No. 1.
@ptbodo: Carla Suarez-Navarro is a human laundry list of all the things you wouldn't want in contemporary pro player. She's short (5-foot-4) and slightly built, not particularly fast, and fond of the volley. She plays a one-handed backhand with frequent use of slice.
Add it all up and Suarez-Navarro takes on the dimensions of a novelty in today's game. But it in winning Doha last week, the 27-year-old Canary Islander once again demonstrated that size, great athleticism and powerful strokes can be neutralized, and don't always shape the outcome of a match.
Some thought it a fluke, or certainly a once-in-a-career run, when Suarez-Navarro won on the red clay at Estoril in 2014 and ultimately climbed over to tops of all those tall, powerful, baseline bangers to rank as high as No. 8. But in the interim, she's demonstrated that she's a top-10 thoroughbred.
Doha represent the second title of her career, and it was Suarez-Navarro's most impressive performance to date. She sliced and diced her way through a succession of opponents, including No. 3 seed Agnieszka Radwanska. Thanks to the win over rising star Jelena Ostapenko in final, Suarez-Navarro has shot to a career-high No. 6.
@natkinESPN: Andy Murray and Great Britain step out as defending Davis Cup champions Friday, but captain Leon Smith says they're "not here to celebrate."
After winning the trophy for the first time in 79 years with a victory over Belgium in November, Britain faces Japan in a first-round tie in Birmingham, England.
Smith warned against complacency.
"It's great we've got another home tie," Smith told Press Association Sport. "We've had a lot of them, but it's great to come out as defending champions.
"At the same time, we've all been around long enough to know that it starts again, and we're not here to celebrate; we're here to win.
"We can enjoy going out there with confidence because we are defending champions, but we're very much back to business as usual. We can't underestimate what is a very good Japanese team."
Murray will lead Britain once more as he returns to the court for the first time since his Australian Open final defeat to Novak Djokovic and subsequent birth of the Scot's daughter, Sophia.
Cuevas added two titles to his résumé this season, in Brazil and Sao Paulo, to take his care total to five, all of them on clay. At the latter, he successfully defended his crown.
Cuevas also achieved a rare feat with seven successive victories against left-handed players -- five in Rio and then two in Sao Paulo.
Beyond his two titles, Cuevas can also boast of his first victory against clay master Rafael Nadal. Coached by former top-10 player Alberto Mancini of Argentina, Cuevas is showing he is now ready to battle successfully against the elite of tennis.
He is now No. 25 on tour, the best Latin American, and ready for the next move: to move into the top 20, something he was very close to achieving last year.
Who's trending high and low
Stan Wawrinka He might be the healthiest of the top-tier players, and Wawrinka is taking advantage of it. He beat a rejuvenated Marcos Baghdadis 6-4, 7-6(13) to win the Dubai Championships on Sunday. Wawrinka has now won his past nine finals on tour. That's coming up big-time in the big moments.
Angelique Kerber: The Aussie Open winner has struggled since the biggest championship of her life. In her opening match in Doha last week, Kerber fell to Zheng Saisai 7-5 6-1 -- this coming after the German was upset by Belinda Bencic in Fed Cup. Kerber admitted she is not "feeling her game or rhythm" since leaving Melbourne.