The former world number one's arrival has coincided with Nadal having one his best campaigns in recent seasons. The 31-year-old has played in seven finals and won four titles including an unprecedented 10th French Open title at Roland Garros.
Moya has been working in tandem with Nadal's long-time coach and uncle Tony Nadal, who has been ever present since the 15-time men's singles Grand Slam champion started on the pro-circuit. He has overseen all his triumphs and supported him during his lows, which have been more than a few in the last few seasons.
Uncle Tony as he is fondly known confirmed that he will take a step back from next season and will not travel to all the events with his nephew with Moya likely to take over as the head coach. Francis Roig is likely to continue as part of his coaching set up.
"Carlos was a good help for all of us," Nadal said after his fourth round win over Alexandr Dolgopolov, as quoted by the Express. "It's great to have him on the team."
"More than a coach, he is one of the best friends that I have on the tour. He came with a lot of motivation, with good ideas and very very positive all the time and believing a lot in what we are doing.
"With him and Toni and Francis [Roig] it's been great. I've been very happy with the way we are working," the Spaniard added.
Nadal is aiming to win his second Grand Slam of the season at the ongoing US Open, but will have to overcome Juan Martin del Potro to book a place in the final. The Argentine, for the second time, denied the fans a chance to watch Roger Federer take on the Spaniard for the first time at Flushing Meadows after he beat the Swiss ace in the quarter-finals.
The 10-time French Open winner is currently on top of the men's singles ranking and will retain his place after the final major of the season. A win will see him extend his lead over Federer, who will take over from Andy Murray as the new world number two.