The 17-time tennis grand slam winner, Roger Federer, hit a road bump on his comeback trail from injury, losing to German teenager Alexander Zverev in three sets at the Hopman Cup in Perth.
Federer went down 7-6 6-7 7-6 in the two-and-a-half hour match, as Germany snatched a 1-nil lead in their Group A tie.
That Federer lost to the 19 year-old, ranked 24 in the world, wasn't a complete surprise; he's done that before.
More surprising was that he led the first set 5-2, and served for it at 5-3, but still lost it and ultimately the match.
Zverev now holds a 2-1 record over Federer, downing him in Halle, Germany last year.
Zverev said it was a tough contest.
"To beat Roger, you really have to play an unbelievable match, from the first point to the last. I thought we both played really well," Zverev said.
"I always play unbelievably against him. It's always nerve-racking to play against him. I always play in front of a big crowd which helps me a lot as well."