Rafael Nadal knew something had to change.
It was nearing midnight in Australia on Friday, and his match against Karen Khachanov of Russia was heading into its third hour. Nadal still had a comfortable lead, but the 25-year-old Khachanov was gaining strength and closing in on the third set. Nadal, a decade older, and just back from a nearly six-month rehabilitation from a chronic foot injury, needed to do whatever he could to avoid one of his classic battles of attrition. Nadal has often won those battles, and could still, but possibly at a significant cost.
At this point in Nadal’s career, how he might win is as important as winning itself.