LONDON (AFP) - Britain's hopes of overcoming Ukraine in the Davis Cup this weekend have been dealt a severe blow after Andy Murray withdrew from a Europe/Africa zone tie due to take place in his native Scotland. Murray, the world number four, has been forced to pull out as a result of a virus that caused him to withdraw from the Dubai Open last week, the Lawn Tennis Association announced on Monday. A spokesman for Murray added: "Following his withdrawal from the Dubai Open, Andy's condition hasn't improved. "After daily visits from the LTA doctor and a number of medical tests, Andy has been told to rest for at least seven days to overcome his virus. "Andy is greatly disappointed that he has to pull out as he was looking forward to playing for Great Britain in front of his home crowd. He will be right behind John Lloyd and the team." Lloyd, the GB captain, insisted his team could cope with the loss of his number one player. "We have five players up here who are desperate to play and they have all impressed me in the last week," he said. "With the support of a vocal home crowd I firmly believe that this is a very winnable match for us." Great Britain dropped down to the Europe/Africa zone in the Davis Cup after losing a playoff in September 3-2 to Austria. That defeat underlined the country's lack of back-up for Murray. The Scot won both his singles rubbers but Alex Bogdanovic lost his two matches while Jamie Murray and Ross Hutchins were beaten in the doubles.