Tennis ball girls were replaced by canine counterparts on Thursday (December 6) at the opening of the Champions Tennis tournament. The animals helped retrieve stray balls between the points from Mansour Bahrami, Juan Carlos Ferrero, Henri Leconte and Mikael Penrnfors during a doubles match. The three dogs, called Hattie Tina and Melvin, were provided by the charity Canine Partners, which trains dogs to help people with disabilities. Canine Partners aftercare manager, Claire Anthony, said that although the dogs were used to retrieving objects such as inhalers and pens, they had to be specially taught to fetch tennis balls. Former British number one Tim Henman helped train the dogs, but at a press conference before their appearance on court, he appeared to doubt whether they`d be as effective as their human counterparts. What do they say about working with animals and children? Don`t do it," he joked. "Ball dogs" are not a novelty in tennis, with them already having appeared on court at the Brazil Open. Running for more than 20 years, the Champions Tennis event features former Grand Slam winners and numbers ones, with the likes of Pete Sampras, Bjorn Borg and John McEnroe previously taking part. The tournament at London`s Royal Albert Hall runs until December 9.