Former Communist Party general secretary Jiang Zemin did not show up at a gathering on Thursday afternoon at which new party chief Xi Jinping praised his predecessor Hu Jintao for standing down fully from his top party posts.
Jiang, 86, had been in the limelight ahead of the once-a-decade power transfer. It was not clear why Jiang did not attend the gathering.
State television reported that a slew of party veterans, including Hu's 96-year-old mentor Song Ping, former premier Li Peng and his successor Zhu Rongji had attended Thursday's gathering.
Xi told the gathering of more than 2,600 party congress delegates and party veterans that Hu and six other members of the previous Politburo Standing Committee had "taken a lead to step down" from all their party posts, showing their "high virtue and nobility of character", a prime-time China Central Television news programme reported on Thursday night.
"We have high respect for them," Xi said.
Hu broke the precedent set by Jiang 10 years ago by not staying on as chairman of the party's powerful Central Military Commission and instead handing leadership of the party and military body to Xi on Thursday.
The Communist Party mouthpiece People's Daily also sang Hu's praises for his full retirement from party offices in an editorial yesterday, saying the move showed his "supreme loyalty" to the party and people.
Analysts have said that by fully retiring from all his party posts, Hu was seeking to end interference by party elders - most notably Jiang - in personnel and policy decisions.
Some said Jiang, who stepped down as party chief in 2002, played a key role in selecting the new leadership, outmanoeuvring Hu in some cases.
A mainland journalist said: "Hu's been waiting for two decades and when his day comes, he chose to go, and that has at least one direct advantage - his predecessor who had lingered for the past 10 years is now too ashamed to show up again."
Jiang voted at the closing session of the party congress on Wednesday and was in good spirits at the opening ceremony last week.