LONDON: Rafa Nadal has withdrawn from next week’s U.S. Open tune-up event in Montreal, Canada due to the same abdominal strain which forced him to miss his Wimbledon semi-final last month, he said on Saturday. World number three Nadal’s quest for a calendar Grand Slam ended after he pulled out of his highly anticipated showdown against Australia’s Nick Kyrgios less than 24 hours before the match. The 26-year-old Nadal, who has won 22 major titles, is a five-time champion at the ATP 1000 event in Montreal, which begins on Monday. “I have been practicing for a while now without serving and started with serves four days ago. Everything has been going well, however yesterday, after my normal practice, I felt a slight bother on my abdominal and today it was still there,” Nadal said in a statement. “After speaking with my doctor we prefer to take things in a conservative way and give a few more days before starting to compete. I am very sad not to finally travel to Montreal and to play a tournament that I have won five times and I love to play.”