Andre Villas-Boas has hailed Michael Essien's return to first team duties after the Ghana midfielder came on against Sunderland on Saturday.
Essien returned for his first appearance of the season as a second half substitute following knee surgery as Chelsea earned a 1-0 victory at home.
The player's return has prompted the manager to welcome his comeback as a timely boost after Chelsea moved within six points of third-placed Tottenham.
"To see a player make the switch from reserve team to full Premier League intensity in such a short period of time is amazing," Villas-Boas said.
"You have to give credit to the medical department who have reduced Michael's absence by a month or a month and a half.
"The team is grateful to have him back. He has always been an inspiration because of the person he is and the player he represents.
"And to see him back on the pitch so quick and with such quality is outstanding and is all down to the medical department and the player's willingness to come back."
Essien, 29, has been sidelined since July, when he underwent surgery after rupturing the anterior cruciate ligament and meniscus in his right knee in preseason training.