Former world number one Ferrero, who retired from playing in 2012, underwent knee surgery and was absent from the Australian Open, where Alcaraz lost in the quarter-finals to Alexander Zverev.
Ferrero, the French Open champion in 2003, returned to his Spanish compatriot's dugout in time for Alcaraz's run to the semi-finals in Buenos Aires before an injured ankle saw the world number two pull out of his opener in Rio de Janeiro.
However, Alcaraz picked up his first title of the season in the Californian desert on Sunday and paid tribute to Ferrero's "special" support.
"It depends on how he's watching me. If I'm struggling a lot, if I'm in problems or not, he tells me depending on the moments," Alcaraz told reporters on Tuesday.
"But one of the things he tells me most is to smile.
"He means a lot to me. It's a great support when I have him in the box. His support is special to me. It's been a long path together, six years now.
"We've done great work together. I spend a lot of time with him at tournaments and (outside) as well. We have a really good relationship in the professional part, but the personal part as well. I've learned a lot from him."
Twice Grand Slam champion Alcaraz is looking to become the first man since Roger Federer in 2017 to complete the 'Sunshine Double' and will face Aleksandar Vukic or Roberto Carballes Baena first in Miami.
"I'm playing great tennis. I'm really happy to be in Miami again, a special place, where I've shown great tennis the past years," said Alcaraz.
"I'm feeling great physically and mentally. I'm ready for this tournament."
