The striker had been absent since a nasty foul left him hobbling off the pitch in some pain early in the emphatic home victory over Malmo on 20 October.

With the aid of the medical staff at Chelsea he has nursed the ankle injury since, returning to outside training during the recent international break and then stepping back onto the pitch on Sunday. According to Thomas Tuchel, that has lifted Lukaku’s spirits, with the Belgian in genuine contention to start against Watford later.

‘We gave him some minutes, and that helps him psychologically,’ said Tuchel.

‘He is happy, he smiles every day, he is determined, and he trains on a very high level. Once we are of the opinion he is fully free, he is ready to go and contribute what he can, which is a lot. He is with the team and a big chance to play [tonight].

‘We believe he can make the difference for us but at the same time we will be patient. He is a big guy, and a big guy with an ankle injury in my opinion needs a bit of time because he puts heavy weight on his ankle for turning, acceleration, deceleration. This is a crucial part of these movements.

‘We have showed with and without him we are capable of scoring and winning, and it’s a process of adapting both ways,’ continued Tuchel, assessing the Belgian’s impact on this Chelsea side.

‘The most important thing is he gains fitness and a physical level where he can start for us. The rest will take care of itself because Romelu is a winner, a champion and is hungry for more.’

Another player who has been without much playing time in recent weeks, albeit for different reasons, is Saul Niguez. The midfielder on loan from Atletico Madrid has started one league game, his debut against Aston Villa, and has only briefly featured off the bench twice in the past month.

However, with N’Golo Kante and Mateo Kovacic ruled out of tonight’s game through injury and Jorginho a doubt, there is a good chance Saul will feature at Vicarage Road. Tuchel has discussed that prospect and, more broadly, the Spaniard’s start to life in SW6.

‘Every single player needs his time to adapt, and Saul needed his time,’ said the boss.

‘He competes with a lot of high-quality players in our midfield. We need to understand him a bit better, not in terms of language but in terms of what are his real strengths when you get to know him, what can he add to the squad and where his unique quality is.

‘It’s the first time he has played for a club other than Atletico,’ Tuchel pointed out.

‘The style of the game is so different from Spain to here, and that teaches us a lesson that everybody needs their individual time to adapt.

‘Since many days ago he is stronger, I feel him a bit more relaxed and at the same time it gives him a little bit more freedom to impose his quality. He is very strong in finishing, and he is very strong in arriving in the box.

‘Where we have injured players in midfield - even Jorgi is doubtful tonight - it’s the moment for him to be ready. I have had the feeling for many days he is ready and can show what he wants to do.’