Claycourt king Rafa Nadal regained his Roland Garros throne after two years in exile with a brutal 6-2 6-3 6-1 mauling of Swiss Stan Wawrinka to complete 'La Decima' on Sunday. Rewinding the clock to the days when he was untouchable on the crushed brick dust, the 31-year-old turned 2015 champion Wawrinka into a human punch bag, winning in just over two hours. This title, a record 10th at a single grand slam in the professional era, was arguably the most impressive of his 15 majors, though, as it arrived three injury-plagued years after the last one when he beat…