Cristiano Ronaldo has now faced Manchester United three times since leaving them nine years ago and on each occasion he has played a key part in the final outcome.
The Portuguese sent over the cross that led to Paulo Dybala’s 17th minute close-range strike and he might have had another goal against his former club but for a flying save by David de Gea.
United – who were late arriving for the game again because of traffic – were outclassed throughout and if it weren’t for De Gea the scoreline could have been humiliating.
It could have been an occasion for Lukaku to silence his critics and outshine United’s former golden boy but the Belgian struggled against a resilient Juventus side.
The Belgium international has just four goals in 11 appearances this season for United.
It’s a different story though for his country having hit ten goals in his last eight matches.
But Mourinho is standing by his main striker, admitting Juve’s defence is tough to break down.
“His moment is not sweet. Not just with the goals he is not scoring,” he said.
“He is not linking well with the team, but he is our striker. We believe in him.
“In the other side there was huge quality. Sometimes people look for Ronaldo or Dybala but in a top team you have to look to [Giorgio] Chiellini and [Leonardo] Bonucci.
“I think Juventus is this type of team that when they are in front its very difficult.
“I think our attacking players, things were not coming. But everyone tried, everyone was strong mentally to try until the end.
“Juventus felt it and they ended the game with an extra central defender to add to the amazing Chiellini and Bonucci.
“It was a really difficult match for us. I thought we could take something but it was not possible.”
Defender Luke Shaw believes his side showing their opponents too much respect was their own downfall.
But Shaw is taking confidence from the other Group H match result, that saw Valencia draw with Young Boys, to boost United’s chances of progressing as they sit two points above the Spanish side.
“I think first half we gave them too much respect we let them play far too easy, in the second half we tried and for some reason again we performed better in the second half, we pushed on but didn’t create many chances and like I said we gave them too much respect,” he said.
“We trained for them, we knew what was coming, in the first half we gave them too much time on the ball we should of been pressing higher.
“At least Valencia didn’t win, now we have to go to Juventus and get a result.”
Away from Manchester, rivals City began to pull their weight like proper Champions League heavyweights when they became the first English team to win at Shakhtar Donetsk in European competition with a comfortable 3-0 win in their Group F match in Kharkiv.
Pep Guardiola’s side waltzed to victory with goals from David Silva, Aymeric Laporte and substitute Bernardo Silva.
What looked a potentially difficult 1,700-mile visit to the Ukrainian champions, who had beaten Guardiola’s men in the group stages last year, was made to look effortlessly routine as the dazzling David Silva orchestrated their dominance.
“We could have scored a lot of goals. We scored three. We are happy,” said David Silva.
“It’s difficult and this is a tough place to come. We have a lot of chances.
“We are playing better every game. We need to improve a little bit more. If we play like this we will get more points.”
City could easily have scored more but the victory put the English champions top of the group on six points, a point clear of Lyon, who drew 3-3 at Hoffenheim, who have two points along with bottom-placed Shakhtar.
CHAMPIONS LEAGUE RESULTS
AEK Athens 0-2 Bayern Munich
Ajax 1-0 Benfica
Shakhtar Donetsk 0-3 Manchester City
Hoffenheim 3-3 Lyon
Real Madrid 2-1 Viktoria Plzen
Roma 3-0 CSKA Moscow
Young Boys 1-1 Valencia
Manchester United 0-1 Juventus