"Last year, I was told I probably needed surgery on my hip, but here I am just nine months later". But the most important thing is to play at my best level.
"I think my backhand is improving every week", he said.
"I also have no idea how I have done it. just hard work".
"I was playing too much to his backhand and I knew that I had to change and move him more and be more unpredictable".
Big-serving South African Kevin Anderson was spotted on a practice court stretching his 6-feet 8-inches (2.03 metres) frame as he prepares to meet the other Spaniard in the semi-finals, Pablo Carreno Busta. The men's final between Nadal and Anderson will be broadcast live on ESPN on Sunday, Sept. 10, at 4 p.m. ET.
Nadal, the overwhelming favourite, has no intention to underestimate Anderson, the lowest-ranked US Open finalist since the ATP rankings began in 1973.
"It's been a long road", Anderson, who overcame a right hip injury past year that had threatened his 2017 campaign, told reporters.
Nadal was won all four career meetings against Anderson, the most recent this year at Barcelona.
Closing in on a third title at Flushing Meadows and 16th grand slam crown, Nadal overcame that so-so start with an overwhelming performance ultimately.
If someone had suggested in the beginning of the year that Roger Federer would win two Grand Slams and Rafael Nadal would take another (and possibly a second), we probably would have rolled our eyes. Del Potro is on a hot streak right now, entering the match having defeated No. 11 Roberto Bautista Agut, No. 6 Dominic Thiem and Federer in his last three outings. I played a couple of matches so-so, but the last three matches have been very positive, and this one was the best one for me. It happened in 2009, when del Potro himself beat Nadal in the semifinals, and then Federer in the final.
"Juan Martin deserves it more".
"I don't know what the turning point was, maybe I got lucky", he said.
Del Potro took that opening set, but Nadal took over the match from there.
"It was an unbelievably tough match on one of the biggest stages in tennis", Anderson, who has lost all four of his previous encounters with Nadal, was reported as saying by BBC Sport. But winning two matches with straight sets is important for me.