Federer stunned by teenager Zverev in Hopman Cup

WION New Delhi, Delhi, India Jan 05, 2017, 08.33 AM(IST)
Roger Federer suffered a setback on his return to competitive tennis after six months of injury layoff. Germany's 19-year-old Alexander Zverev stunned the 17-time grand slam winner at the Hopman cup. Here's more to this story.