The world number one was not able to play at London's O2 Arena last year because of knee problems but since returning in February his form has been sensational.
Nadal has won 10 tournaments, including two grand slam titles, and he is chasing the one major trophy missing from his CV to complete a dream season.
Ferrer provided little opposition, the third seed failing to find the form that helped him beat Nadal in the semi-finals of the Paris Masters on Saturday as he went down 6-3 6-2 in just an hour and 14 minutes.
Nadal said: "It is a fantastic stadium. It's a stadium that I really love. It's one of the best stadiums that I ever played in.
"I enjoy it every time. First of all, what it means to be playing here, because it shows you had a great season, and at the same time the atmosphere, the lights.
"Even if I was not able to play my best a lot of times here, I really have great feelings every time I have the chance to be playing in this stadium. Last year was a big miss for me."
Nadal made the final in 2010, losing to Roger Federer, but he has also failed to reach the semi-finals twice at the O2.
A straight-sets victory over Stanislas Wawrinka on Wednesday would book his place in the last four and also secure the year-end number one ranking ahead of Novak Djokovic.
Nadal said: "I've always come here with motivation to play well.
"For some reason you have places that the conditions are a little bit worse for you. But that doesn't mean that one year you have special motivation.
Every time I am able to play in the World Tour Finals it has been a special feeling for me.
"Sometimes I didn't play my best. Other times, I played well. I had a few chances without a positive end. But I going to try to play a good match tomorrow and create another chance to be in the semi-finals again."
Ferrer had ended a nine-match losing streak against his compatriot in Paris but it was a different story from the start here.
The extra bounce suited Nadal better and only a late rally from Ferrer prevented him losing the second set to love.
It was not a high-quality match, with half of the points being decided by unforced errors.
Asked what had made the difference from Paris, Nadal said: "What really changed is nothing in three days. But probably he arrived a little bit more tired after playing the final there. The court is a little bit slower.
"I played with a little bit more calm than the other day. And, in my opinion, he didn't have the chance to hit the winner as easily as he did three days ago."
Ferrer, who now faces a crunch clash against Tomas Berdych on Wednesday, took few positives from his performance.
He said: "I think it was not a good day. Rafael played well. In all the match I didn't have a good feeling.
"Tomorrow I think I will play better. I hope so. I have to be positive. It was a bad day, but it's good to have a bad day here in the round robin because I have one chance for tomorrow and on Friday."
From next year there will once again be a week in between the Paris Masters and the World Tour Finals, although Ferrer was reluctant to blame the quick turnaround.
He said: "I think the conditions are similar. Maybe I'm a little bit tired. I played a lot of matches these seven weeks.
"It's not an excuse. But to beat these type of players, it's very important to rest and to be in perfect condition."