Turin: Juventus star Cristiano Ronaldo warned he was 'back' and ready for Tuesday's Champions League meeting with old rivals Atletico Madrid in Turin.
Coach Maurizio Sarri said the 34-year-old Portugal international's fitness still had to be assessed before the Group D clash as he battles a knee problem.
But the 34-year-old showed his eagerness to play by posting a photo on Twitter with the caption: "I'm back," followed by an emoji of a flexed bicep.
Ronaldo has a long history with the Spanish side going back to his nine years with city rivals Real Madrid.
The five-time Ballon d'Or winner scored 22 goals against Atletico for Real, including in the 2014 Champions League final triumph. He also hit the winning spot-kick as they were defeated in the final again two years later.
In last season's Champions League, the Spanish were 2-0 winners in the first leg of their last 16 tie, but a Ronaldo hat-trick in Turin in March denied them a quarter-final berth.
"I have five Champions Leagues, these guys zero," Ronaldo had declared after the defeat in Madrid, holding up five fingers to the home fans throughout the game.
This season Ronaldo has scored just once in the Champions League and was furious after being substituted by coach Maurizio Sarri in their last game against Lokomotiv Moscow, also being hauled off before the hour in the following game against AC Milan.
In characteristic defiant style he hit back with four goals to qualify holders Portugal for Euro 2020.
But he was rested for Saturday's Serie A game against Atalanta which Juventus won 2-1 thanks to a Gonzalo Higuain double to stay top of the Italian league.
"Cristiano trained with his teammates yesterday (Sunday)," Sarri told a press conference at the Juventus Stadium.
"It seems that his condition is improving but we still have to evaluate between today and tomorrow.
"The positive thing he was able to play throughout the training session with his teammates."
Atletico coach Diego Simeone knows what to expect from a player who holds the record of Champions League goals with 127.
"Ronaldo is a champion, we have always suffered a lot against him. He is number one, but I don't think it's Ronaldo against Atletico because Juve is a great team.
"I have no doubt, Juventus will be the protagonist again this year."
Atletico midfielder Koke added: "We consider the team as a whole, not just Ronaldo.
"Ronaldo had scored a lot of goals against us, we'll see if he will play one of his typical matches tomorrow."
Sarri said he had "a good relationship with Ronaldo" despite the player's harsh words in his direction at being substituted.
"If a player who has won so much is angry about being substituted, it means he still has a lot of motivation, and this is something positive," said the former Chelsea and Napoli coach.
Juventus are already through to the last 16 and want to finish top of their group with second-placed Atletico needing a win to guarantee their place.
The Italian champions will be without defender Matthijs de Ligt, with a dislocated shoulder, with forward Federico Bernardeschi, who bruised his chest, in doubt.
Atletico's Portugal forward Joao Felix is also fighting for fitness.
But Sarri conceded he was spoilt for choice up front between Ronaldo, Paulo Dybala and Higuain.
"We have three very strong strikers for just two roles, I think it is an ideal situation," continued the Juventus coach.
"Playing Dybala, Higuain and Cristiano all together is difficult because of their characteristics, but all three know how to play really well and are comfortable with each other."
Higuain, who has scored five goals this season, said he was not trying to take Ronaldo's throne.
"I don't have to steal anything from anyone," said the 31-year-old, who played alongside Ronaldo at Real Madrid.
"We know who Ronaldo is, a winner. I try to help the team win, we are all important and crucial, both those who play and those who don't play.
"In the long run, this is what leads a team to winning things."