PERTH, Australia — Roger Federer found himself overmatched — just — by a younger and stronger-serving opponent on Wednesday, losing 7-6 (1), 6-7 (4), 7-6 (4) to 19-year-old Alexander Zverev of Germany at the Hopman Cup.
The 35-year-old Federer was playing his second match since returning from a six-month layoff because of a left knee injury. He led 5-2 in the first set, but ran into an opponent whose first-serve percentage exceeded 80
But