Manchester City striker Sergio Aguero scored 10 minutes into his return from injury on Wednesday, but Pep Guardiola has ruled him out of starting Saturday's Manchester derby.
The Argentinian missed the beginning of the season after having knee surgery in the summer and suffered a further setback with a hamstring injury shortly after his comeback.
After stepping up his training with the first team, Aguero was a 67th-minute substitute against Marseille and prodded home City's second from close range in their 3-0 win to close out the Champions League group stage.
"His instinct to score will always be there," Guardiola said after the game. "He had three or four training sessions, his reaction was good. He played 25 minutes and scored a goal but it's step-by-step.
"The most important thing is his reaction tomorrow."
But asked if Aguero has any chance of starting the match against Manchester United at Old Trafford, Guardiola emphatically replied: "No."
Aguero has now scored 41 Champions League goals to move level with PSG's Neymar as the second-top South American goalscorer in the competition behind Barcelona's Lionel Messi on 118.
Summer signing Ferran Torres started the match as City's No.9 and despite being a winger, the Spaniard is setting his own records as a goalscorer.
The 20-year-old scored the opener to take his tally to five goals from City's six group games, after also netting in his last European game before leaving Valencia.
Real Madrid legend Raul is the only Spaniard to have scored more Champions League goals before turning 21.
Torres' form gives Guardiola a number of options ahead of the trip to Old Trafford, where the pressure will be on United boss Ole Gunnar Solskjaer after his side's disastrous Champions League exit.
"I'm really happy for the way we played in all the games without exception," Guardiola added of the Champions League. "We scored goals and we conceded few.
"Now it’s time to celebrate and tomorrow I am going to think about the Premier League and the derby. We have two days to think about it."
