Contemplating a Murray-McEnroe coaching partnership; more mailbag

John McEnroe has expressed interest in coaching Andy Murray, who split with Ivan Lendl in March.

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My attitude: If you have the capacity for accuracy, why not maximize it? Let the players issue as many challenges as they fit. Those abusing the system or challenging excessively will be exposed and deterred by the court of public opinion. And, as Fred notes, there is an irony that on clay, which doesn't use Hawk-Eye, appeals are limitless.

Rafael Nadal suffered two surprising losses in clay tournaments he has previously dominated.

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• You will have a hard time topping this for long-lost siblings.