Barcelona have announced Tito Vilanova's operation on his parotid gland had gone "as expected" as the 44-year-old began a second battle with cancer.
Vilanova, who also had a tumour removed from his throat in November last year, will now start six weeks of chemotherapy.
In a statement, the club said: "Vilanova's surgical procedure has gone as expected. His clinical progress will determine how long he remains in hospital. The expected timeframe has been maintained. Tito asks for his privacy and confidentiality to be respected."
Captain Carles Puyol said the Barca players have drawn strength from Eric Abidal's return to good health as they come to terms with news of Vilanova's need for further cancer treatment.
Abidal returned to training Wednesday for the first time since he needed a liver transplant in April.
Puyol said: "You're never prepared to hear news like this, but Abidal's example gives the team strength and I'm sure Tito's case will do the same. It's not just an example to us but to the man in the street, proving that if you fight hard, everything will be fine. The best way to support him is to keep moving forward. It is a severe blow but we must get up and keep on playing. This team has always done that and will do so again.''
Abidal's return was a significant step in his bid to continue his career, although he admitted he had been left thinking only about his ailing boss.
"I confirm to you that I have started again the collective training with the group,'' he wrote on his Facebook page today. "I hope to come back soon on the fields, but I can't stop thinking of our coach, Tito Vilanova: I wish him and his family a lot of courage!''
Barcelona held a specifically-convened press conference last night in which president Sandro Rosell offered Vilanova the club's unconditional support.
Rosell, who was flanked by on-field leaders Puyol, Xavi, Andres Iniesta and Victor Valdes, revealed assistant manager Jordi Roura would take interim charge but that he expected Vilanova to quickly return to the touchline.
The club even opened the door for Vilanova to come back during his recovery, with a statement saying his "treatment may be compatible with his work life''.
"Tito is strong, very strong. He's shown us that and we're convinced he'll be back with us very soon,'' Rosell said. "We want to express our unconditional support to Tito and his family. We thank everyone for their support. We have complete confidence in the team. The club is very strong and united, we're capable of overcoming adversity.''
Barca travel to Real Valladolid on Saturday before the winter break and sporting director Andoni Zubizarreta emphasised Vilanova, who has led the La Liga leaders to their best ever start, remained in charge.
"Tito is our coach and will continue to be our coach,'' he said. "Jordi (Roura) will be on the sidelines for Valladolid, but all the rest is pure speculation.''
Zubizarreta also expressed his shock at the news, saying: "It was difficult news to hear. Tito's only concern has centred on his children and his family. The only person he has not spoken of is himself."