Hopman cup is a useless exhibition and doesn’t countEveryone has a loss like that.
e.g. Murray himself in that 2010 Hopman Cup final against Robredo. His underdog partner gave GB a 1-0 lead and then Andy "I'm not going to lose" Murray came out oozing arrogance, playing like a million dollars and setting up a matchwinning lead. Then the UEs rained down late in the second set and Robredo pounced as he does. I was amazed that Murray made the AO final just weeks after that public pieing.
The point is that Hopman was not exhibition but an official ITF competition, which required conditions to participate (ITF ranking), but did not give points through ATP, nor did it integrate into h2h by ATP.You obviously haven't watched a lot of the Hopman Cup.
Uh no in his prime, he won slams and was consistently making it to the last few rounds in the biggest tournaments. Now he is barely beating Nishioka and getting straight setter by FAA. Also got destroyed by his pigeon Raonic. He can’t even make it to the second week anymore. 15% sounds about right.No, you are clueless if you think this seriously. 15% he wouldn't win any match on the main tour. Even 30% was a hyperbole.