Maria Sharapova and Madison Keys have withdrawn from the 2018 WTA Dubai Duty Free Tennis Championships starting next week due to injury and illness, organisers said Thursday. Five-time grand slam winner Sharapova, <a href="https://www.thenational.ae/sport/tennis/maria-sharapova-confirmed-to-play-in-2018-dubai-duty-free-tennis-championships-1.700570">who was handed a wild card for Dubai</a>, suffered a shock defeat in the first round of the Qatar Open on Monday, dumped out in three sets by outsider Monica Niculescu. The Romanian, ranked No 92 in the world, 51 places behind the Russian, won 4-6, 6-4, 6-3. Organisers said in a statement Sharapaova had withdrawn owing to forearm strains. American world No 14 Keys, who was meant to make her Dubai debut next week, has withdrawn due to illness. Last year’s US Open runner-up lost her second-round match in Doha on Wednesday to Catherine "CiCi" Bellis 2-6, 6-3, 6-0 on Wednesday. “Unfortunately both Maria Sharapova and Madison Keys have regretfully had to withdraw from the Dubai Duty Free Tennis Championships due to injury and illness," said Dubai tournament director Salah Tahlak. "We are sorry that neither Maria nor Madison will be able to play in Dubai, but we still have one of the strongest fields ever assembled for the WTA event. "Maria said that she is very sorry she cannot be here and hopes to come back next year. We wish her and Madison a speedy recovery.” <strong>________________</strong> <strong>Read more:</strong> <strong>________________</strong> Despite the two high-profile withdrawals, organisers confirmed Thursday that French Open champion Jelena Ostapenko has been added to a stellar line-up now containing nine of the world's top-10 players. The world No 6 joins a field headlined by Simona Halep, the world No 2, along with defending champion and world No 3 Elina Svitolina. Garbine Muguruza, the Wimbledon champion ranked fourth in the world, is also set to compete alongside world No 5 Karolina Pliskova. Also taking their places in the Premier-level event are France's world No 7 Carolina Garcia, Germany's former world No 1 Angelique Kerber, now ranked No 9, and her compatriot Julia Goerges, who rose to No 10 last week. The 2018 Dubai Duty Free Tennis Championships will begin with the WTA event on February 19 with the final scheduled for February 24 at the Aviation Club in Dubai. The ATP tournament will then follow on February 27 with the final on March 3.