Wimbledon champion Muguruza was ahead 2-1 in the deciding set against Serbia's Aleksandra Krunic in the second round of the warm-up tournament for the season's first Grand Slam event when she collapsed to the ground following a serve.
The Spanish top seed was unable to continue and handed the match to Krunic 5-7, 7-6 (3), 2-1.
"I felt in trouble in the second set when I was 2-0 up," Muguruza said. "I started to feel my calves were cramping."
Muguruza had won a tight first set and appeared heading for a straight sets win over Krunic when she opened up a 5-2 lead in the second.
— #BrisbaneTennis (@BrisbaneTennis) January 2, 2018
Murray suffered a right hip injury in 2017 and has not played on the ATP tour since losing a tough five-setter to American Sam Querrey in the quarter-finals at Wimbledon.
He said on Sunday he felt in great shape at the start of the new season and said he was confident he would play in Brisbane.
However, on Tuesday he announced he had withdrawn from the tournament.
Murray joins top seed and world number one Rafael Nadal, who withdrew from the tournament late last week, on the sidelines.
Andy Murray has unfortunately had to withdraw from the Brisbane International due to a right hip complaint pic.twitter.com/trjo0Vovym
— #BrisbaneTennis (@BrisbaneTennis) January 2, 2018
“I’m very disappointed. I came here with every intention of making a strong start to the year but sadly my team and I don’t feel that I’m where I need to be just yet to compete at the highest level,” Murray was quoted as saying by the tournament’s official Twitter account.
With so many fitness concerns surrounding a host of top players at the start of the new tennis season, opportunity might strike for others who have been waiting in the wings for a chance at claiming a maiden Grand Slam title.
Novak Djokovic postponed his start to 2018 citing elbow pain and hasn’t played since Wimbledon. Andy Murray is making his first appearance since Wimbledon in Brisbane this week but admits he may have to settle for top-30 level of play following a six-month absence due to hip injury.
There is no news from the Stan Wawrinka camp since he pulled out of the Mubadala World Tennis Championship. The Swiss also hasn’t played a match since Wimbledon and had double knee surgery in August. He’s back practicing but will no doubt need some time before he performs at his best once again.
Milos Raonic also had injury trouble in 2017 and returns to action in Brisbane, with a new coaching team in tow.
Kei Nishikori delayed his start to 2018 by pulling out of Sydney injured.
World No. 1 Rafael Nadal pulled out of Abu Dhabi and Brisbane to fully recover from a knee injury but will fly to Melbourne soon in preparation for the Australian Open.
With defending champion Roger Federer being an obvious choice as favourite for the title in Melbourne, who are the men we should be looking at as potential first-time Grand Slam winners Down Under this month?
The Bulgarian finished 2017 in the best way possible, going undefeated at the ATP Finals to claim his biggest title to date in London. He showed confidence and swagger under the lights of the O2 Arena and says the pressure he used to feel on his shoulders in the past has now been lifted as he focuses on his love for the game and enjoys his time on court.
Dimitrov is the defending champion in Brisbane and had a great run Down Under last year where he made the semi-finals at the Australian Open, before losing a five-set heartbreaker to Nadal. Will he be able to do better than his 10-1 win-loss start to the season last year in Australia? The opportunity is there for the world No. 3 to go and grab it!
Everything is always way more fun Down Under…
— Reem Abulleil (@ReemAbulleil) December 31, 2017
Another player carrying momentum from the end of 2017 is Belgium’s David Goffin. The world No. 7 defeated Nadal and Federer at the ATP Finals in London on his way to the title match before falling to Dimitrov. He made the quarter-finals at the Australian Open last year and is already showing great form Down Under as he put in a strong performance to defeat Alexander Zverev in the Hopman Cup in Perth on Monday. With a top-eight seeding and a favorable draw, Goffin could be a threat in Melbourne this month.
The 20-year-old hasn’t made it past the fourth round at a Grand Slam yet but his achievements so far in his young career cannot be ignored. The German won two Masters 1000 titles last year, defeating Djokovic in the final in Rome, and Federer in the final in Canada. He won three more trophies in 2016 and is the current world No. 4. He is coached by his father Alexander Sr. and ex-world No. 1 Juan Carlos Ferrero. A Grand Slam breakthrough certainly beckons.
Many argue that Nick Kyrgios is not ready to win a major due to lack of discipline, lack of direction as continues to travel without a coach, and the struggle he constantly has within himself about his career as a tennis player. Yet the young Aussie’s talent is undeniable and he did reach two Grand Slam quarter-finals as a teenager.
It’s been three years since he’s made that stage at a major but we’ve seen glimpses of the kind of hot streak he can produce when he beat Djokovic in back-to-back tournaments last year in Acapulco and Indian Wells, and his three-set semi-final against Federer in Miami was arguably the best match on tour in 2017. Can he keep it together for seven matches over two weeks? It’s about time he showed us that he can.