The world No.2, playing his first singles match since he crashed out in the fourth round of the US Open in September, was beaten by the American world No.31 over three sets, with Paul overcoming a tough start to win 3-6 7-6 6-1.
Nadal, 36, refused to blame his shock defeat to injury despite suffering with abdominal problems in the second half of the year.
Instead, the Spanish 22-time major winner put it down to a lack of time spent on the ATP Tour, with Nadal taking time off in recent months after the birth of his first child.
Asked if his injury played a part in Paul’s surprising victory, Nadal said: ‘It’s okay, no, all the credit to Tommy.
‘Things that happens sometimes. But no, it’s good, no? I think he played aggressive, a lot of great shots.
‘I had my match in that second set with set and break. I played terrible game there. Yeah, I didn’t deserve the victory playing that bad in that key moment, no.
‘[There has been] a lot of things going on the last couple of months, without a doubt.
‘It’s true that for the last five months I didn’t spend enough days on the Tour.
‘I don’t even say competing on a tennis court. I say on the Tour. Practicing with the guys. That’s what I need.’
Nadal was also quizzed about the upcoming ATP Finals, which will be his last event of 2022.
He added: ‘For me [it is] difficult to imagine now arriving in the World Tour Finals in enough good shape to win a tournament that I didn’t win during all my tennis career.
‘I am going to try, if nothing happens, if I am feeling OK, to be there a little bit earlier than usual and have some practices.
‘Just give myself a chance to enjoy another Finals. You never know when is going to be the last, especially at my age.
‘So I’m going to give my best to enjoy this one, and then next years of course I’m going to fight to be back there.’
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