Davidovich Fokina, 26, had just beaten Bosnian Damir Dzumhur in five sets in the first round when Puerta suddenly broke all ties with the Spaniard.
Rumours circulated that Davidovich Fokina had fired Puerta after a fight in training, but the 23rd-ranked Spaniard denied that in an interview with Marca following his second-round defeat to Thiago Agustin Tirante.
"There was no fight with Puerta. After my match against Dzumhur, he told me he was going back to the hotel. Two hours later, I received a very long message from him saying he was leaving for good," Davidovich Fokina revealed.
Puerta had previously worked with Brandon Nakashima and Laslo Djere, from whom Davidovich Fokina had heard similar stories after the fact.
"He then took a flight to Miami without informing the rest of the team. Later, I heard he'd done the same thing to a couple of players before. It seems like this is normal for him. He's let us down as a person, and I'm not going to chase after him. He was the one who decided not to continue, at least until the end of the tournament. It's not my problem; he's an adult and can make his own decisions," the Spaniard continued.
"We had a very good relationship. He has blocked both my wife and me. I considered him a good person until now. I don't wish him any harm, but I hope future players are careful when working with him."
Eight-year doping ban
Puerta reached the final of the French Open in 2005, but lost in four sets to Rafael Nadal.
Four months after the tournament, Puerta received an 8-year doping ban after testing positive for etilefrine, a banned cardiorespiratory stimulant. It was the second time he'd been caught after testing positive for a banned anabolic steroid in 2003.
Puerta's sentence was reduced to two years after the Argentine appealed to the CAS, but later admitted that he lied in his case defence.